Memory devices with a transistor that selectively connects a data line to another data line

ABSTRACT

In an example, a memory device has a first string of memory cells selectively connected to a first data line, a second string of memory cells selectively connected to a second data line, and a transistor that selectively connects the first data line to the second data line, thereby permitting connecting the first and second data lines in series before programming or sensing memory cells of the first and second strings of memory cells.

FIELD

The present disclosure relates generally to memory devices, and, inparticular, the present disclosure relates to memory devices with atransistor that selectively connects a data line to another data lineand methods for programming and sensing.

BACKGROUND

Flash memory devices (e.g., NAND, NOR, etc.) have developed into apopular source of non-volatile memory for a wide range of electronicapplications. Non-volatile memory is memory that can retain its datavalues for some extended period without the application of power. Flashmemory devices typically use one-transistor memory cells. Changes inthreshold voltage of the cells, through programming (which is sometimesreferred to as writing) of charge-storage structures (e.g., floatinggates or charge traps) or other physical phenomena (e.g., phase changeor polarization), determine the data value of each cell. Common uses forflash memory and other non-volatile memory include personal computers,personal digital assistants (PDAs), digital cameras, digital mediaplayers, digital recorders, games, appliances, vehicles, wirelessdevices, mobile telephones, and removable memory modules, and the usesfor non-volatile memory continue to expand.

A NAND flash memory device is a common type of flash memory device, socalled for the logical form in which the basic memory cell configurationis arranged. Typically, the array of memory cells for NAND flash memorydevices is arranged such that the control gate of each memory cell of arow of the array is connected together to form an access line, such as aword line. For example, a row of memory cells might be those memorycells commonly connected to an access line. Columns of the array mightinclude strings (often termed NAND strings) of memory cells connectedtogether in series between a pair of select transistors, e.g., a sourceselect transistor and a drain select transistor. Each source selecttransistor is connected to a source, while each drain select transistoris connected to a data line, such as bit line. For example, as usedherein when elements are connected they are electrically connected,e.g., by means of an electrically conductive path. As used herein, whenelements are disconnected, for example, they are electricallydisconnected (e.g., electrically isolated) from each other.

A “column” may refer to memory cells that are commonly connected to adata line. It does not require any particular orientation or linearrelationship, but instead refers to the logical relationship betweenmemory cell and data line. Note, for example, that for an array having aplurality of memory blocks, a string of memory cells of each memoryblock might be selectively connected to a common data line through adrain select transistor.

A row of memory cells can, but need not, include all memory cellscommonly connected to an access line. A row of memory cells mightinclude every other memory cell commonly connected to an access line.For example, memory cells commonly connected to an access line andselectively connected to even data lines may be a row of memory cells,while memory cells commonly connected to that access line andselectively connected to odd data lines may be another row of memorycells. Other groupings of memory cells commonly connected to an accessline may also define a row of memory cells. For certain memory devices,all memory cells commonly connected to a given access line might bedeemed a physical row, while those portions of the physical row that areread during a single read operation or programmed during a singleprogram operation (e.g., even or odd memory cells) might be deemed alogical row, sometimes referred to as a page.

Some memory devices might include stacked memory arrays, e.g., oftenreferred to as three-dimensional memory arrays. For example, a stackedmemory array might include a plurality of vertical strings (e.g., NANDstrings) of memory cells, e.g., connected in series, between a sourceand a data line. The term vertical may be defined, for example, as adirection that is perpendicular to a base structure, such as a surfaceof an integrated circuit die. It should be recognized the term verticaltakes into account variations from “exactly” vertical due to routinemanufacturing and/or assembly variations and that one of ordinary skillin the art would know what is meant by the term vertical.

Memory cells, such as non-volatile memory cells, can be programmed tohave a single bit, e.g., during single-level programming, or multiplebits, e.g., during multilevel programming. For example, memory cellsprogrammed to have a single bit may sometimes be referred to assingle-level cells (e.g., SLCs), and memory cells programmed to havemultiple bits may sometimes be referred to as multilevel cells (e.g.,MLCs).

A respective data value (e.g., as represented by a bit pattern) may beassigned to each of a plurality of levels, where each level correspondsto a respective data state. That is, for example, a bit pattern of Kbits might be assigned to each of the 2^(K) program levels, where Kmight be an integer greater than or equal to one (1).

For single-bit-per cell programming, for example, K may be 1, and thus asingle bit may be assigned to each of the two program levels, e.g.,where each of the two program levels corresponds to a distinct range ofthreshold voltages (Vts). For example, a single-bit (e.g., two-level)cell might be assigned a bit value of 1 when it is at its lowest programlevel, corresponding to a range of Vts, e.g. that might be an eraseddata state, and might be assigned a bit value of zero (0) when it is atits highest program level, corresponding to another range of Vts, e.g.,that might be referred to as a programmed data state.

For multi-bit-per-cell programming (e.g., K greater than 1), forexample, each level (e.g., data state) may be characterized by acorresponding distinct range of threshold voltages (Vts) of a pluralityof distinct ranges of threshold voltages that can be stored on themultilevel memory cells. A margin (e.g., a certain number of volts),such as a dead space, may separate adjacent threshold-voltage ranges,e.g., to facilitate differentiating between data values. This technologypermits the storage of two or more bits per memory cell.

A page buffer, for example, might be connected to a data line that isselectively connected to a memory cell, such as a target memory celltargeted for programming during a program operation or sensing, e.g.,during a read operation. In some examples, there may be a page bufferfor each of the bits assigned to a multi-bit-per-cell memory cell. Thatis, for example, for a K-bit memory cell there might be N=K pagebuffers.

Some memory devices, for example, might be configured to program memorycells to have different numbers of bits. For example, a target memorycell might be assigned K bits, e.g., while a memory device is operatingin one mode, and the target memory cell might be assigned fewer than Kbits, e.g., while operating in another mode. For example, when K bitsare assigned to the target memory cell all N=K page buffers may be used,but when fewer than K bits are assigned to the target memory cell fewerthan N=K page buffers may be used.

In some examples, memory cells might be used to store two bits per cell(e.g., K=2) when a memory device is operating in a two-bit-per-cell(e.g., a four-level) mode. For example, there might be two page buffersconnected to the data line that is selectively connected to the targetmemory cell, one page buffer for each of the two bits. However, when thememory device is operating in a single-bit-per-cell mode (K=1), thetarget memory cells might be used to store a single bit, and only one ofthe two buffers might be used for the single bit, while the other of thetwo buffers might not be used.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an example of a portion of a memoryarray.

FIG. 2 is a schematic diagram of another example of a portion of amemory array.

FIG. 3 is a schematic diagram of another example of a portion of amemory array.

FIG. 4 presents a timing diagram for an example of a programmingoperation.

FIG. 5 presents a timing diagram for an example of a sensing operation.

FIG. 6 is a schematic diagram of another example of a portion of amemory array.

FIG. 7 presents a timing diagram for another example of a programmingoperation.

FIG. 8 is a simplified block diagram of an electronic system, accordingto an embodiment.

DETAILED DESCRIPTION

In the following detailed description, reference is made to theaccompanying drawings that form a part hereof, and in which is shown, byway of illustration, specific embodiments. In the drawings, likenumerals describe substantially similar components throughout theseveral views. Other embodiments may be utilized and structural,logical, and electrical changes may be made without departing from thescope of the present disclosure. The following detailed description is,therefore, not to be taken in a limiting sense.

FIG. 1 is a schematic diagram of an example of a portion of a memoryarray. A string 110-1 (e.g., a NAND string) of series-connected memorycells 112-1 (e.g., memory cells 112-1-1 to 112-1-M), such asnon-volatile memory cells, may be connected to (e.g., in series with) aselect transistor 114-1, such as a source transistor, at one of itsends, and to (e.g., in series with) a select transistor 116-1, such as adrain transistor, at an opposite one of its ends. The memory cells 112-1in string 110-1 may be a portion of a group of memory cells. Forexample, memory cells 112-1 in string 110-1 may be a portion of a block126-1 of memory cells, e.g., that may be erased concurrently. As usedherein, multiple acts being performed concurrently will mean that eachof these acts is performed for a respective time period, and each ofthese respective time periods overlaps, in part or in whole, with eachof the remaining respective time periods. In other words, those acts areconcurrently performed for at least some period of time.

Select transistor 114-1 may be connected to (e.g., in series with) asource 120-1 and may selectively electrically connect string 110-1 to(e.g., in series with) source 120-1. Select transistor 116-1 may beconnected to a data line 125-1, such as a bit line, and may selectivelyelectrically connect string 110-1 to (e.g., in series with) data line125-1. Respective ones of memory cells 112-1-1 to 112-1-M may berespectively connected to respective ones of access lines 128-1-1 to128-1-M, such as word lines. For example, control gates of therespective ones memory cells 112-1-1 to 112-1-M may be respectivelyconnected to or may respectively form a portion of the respective onesof access lines 128-1-1 to 128-1-M. A control gate of select transistor114-1 may be connected to a select line 130-1, such as a source selectline, and a control gate of select transistor 116-1 may be connected toa select line 132-1, such as a drain select line.

A string 110-2 (e.g., a NAND string) of series-connected memory cells112-2 (e.g., memory cells 112-2-1 to 112-2-M), such as non-volatilememory cells, may be connected to (e.g., in series with) a selecttransistor 114-2, such as a source transistor, at one of its ends, andto (e.g., in series with) a select transistor 116-2, such as a draintransistor, at an opposite one of its ends. The memory cells 112-2 instring 110-2 may be a portion of a group of memory cells. For example,memory cells 112-2 in string 110-2 may be a portion of a block 126-2 ofmemory cells, e.g., that may be erased concurrently.

Select transistor 114-2 may be connected to (e.g., in series with) asource 120-2 and may selectively connect string 110-2 to (e.g., inseries with) source 120-2. Select transistor 116-2 may be connected to(e.g., in series with) a data line 125-2, such as a bit line, and mayselectively connect string 110-2 to (e.g., in series with) data line125-2. Respective ones of memory cells 112-2-1 to 112-2-M may berespectively connected to respective ones of access lines 128-2-1 to128-2-M, such as word lines. For example, control gates of therespective ones memory cells 112-2-1 to 112-2-M may be respectivelyconnected to or may respectively form a portion of the respective onesof access lines 128-2-1 to 128-2-M. A control gate of select transistor114-2 may be connected to a select line 130-2, such as a source selectline, and a control gate of select transistor 116-2 may be connected toa select line 132-2, such as a drain select line.

A transistor 150, such as a pass transistor, may be connected betweendata lines 125-1 and 125-2. For example, transistor 150 may be connectedto (e.g., in series with) data line 125-1 and to (e.g., in series with)data line 125-2 and may selectively electrically connect data line 125-1to (e.g., in series with) data line 125-2. That is, for example, whentransistor 150 is activated, transistor 150 electrically connects dataline 125-1 to (e.g., in series with) data line 125-2, and whentransistor 150 is deactivated, transistor 150 electrically isolates dataline 125-1 from data line 125-2. A control gate of transistor 150 may beconnected to a control line 152, for example.

A sense amplifier 155, page buffers 158-1 and 158-2, and a data latch160 may be connected to (e.g., in series with) data line 125-2, and thusmay be selectively connected to (e.g., in series with) data line 125-1by transistor 150. When string 110-1 and/or string 110-2 are beingoperated in a multi-bit-per-cell mode of operation, e.g., where thememory cells in string 110-1 and/or string 110-2 are operated asfour-level (e.g., two-bit) memory cells and are used to store two bitsof data, page buffers 158-1 and 158-2 might be respectively used forrespective ones of different bits of the two bits of data of a two-bitmemory cell, e.g., of string 110-1 or string 110-2. For example,respective ones of page buffers 158-1 and 158-2 might be respectivelyused to receive respective ones of the two bits to be programmed to atwo-bit memory cell, e.g., of string 110-1 or string 110-2, or torespectively receive respective ones of the two bits that are read froma two-bit memory cell, e.g., of string 110-1 or string 110-2. Data latch160 may be connected to an input/output (I/O) bus 162.

When strings 110-1 and 110-2 are being operated in a two-level mode(e.g., a single-bit-per-cell mode) of operation, e.g., where the memorycells in strings 110-1 and 110-2 are operated as single-bit memory cellsand the memory cells in strings 110-1 and 110-2 are used to store asingle bit of data, page buffers 158-1 and 158-2 might be respectivelyused for data corresponding to a selected memory cell of string 110-1and a selected memory cell of string 110-2. For example, page buffers158-1 and 158-2 might be respectively used to receive one bit to beprogrammed to the selected memory cell of string 110-1 and one bit to beprogrammed to the selected memory cell of string 110-2 or to receive onebit read from the selected memory cell of string 110-1 and one bit readfrom selected memory cell of string 110-2.

In other examples, there might be additional page buffers, such as thepage buffers 158-3 to 153-N indicated by dashed lines in FIG. 1. Forexample, page buffers 158-1 to 158-N may be connected to (e.g., inseries with) data line 125-2, and thus may be selectively connected to(e.g., in series with) data line 125-1 by transistor 150. Note, forexample, that N=2 for the examples discussed above in conjunction withpage buffers 158-1 and 158-2.

In some examples, page buffers 158-1 to 158-N might be used when string110-1 and/or string 110-2 might be operated in an K-bit-per-cell mode ofoperation or when strings 110-1 and 110-2 are being operated in anm-bit-per-cell mode of operation, where K is less than or equal to N andgreater than m. In some examples, K, m, and/or N might be positiveintegers. Note, for example, that K=N=2 and m=1 for the examplesdiscussed above in conjunction with page buffers 158-1 and 158-2.

For a K-bit-per-cell mode of operation, for example, the memory cells instring 110-1 and/or string 110-2 may be operated as K-bit memory cellsand may be used to store K bits of data. In some examples, a K-bitmemory cell might be a 2^(K)-level memory cell, where the K bits mightbe stored at one of the 2^(K) levels. For an m-bit-per-cell mode ofoperation, for example, memory cells in strings 110-1 and 110-2 mayoperated as m-bit memory cells, and the memory cells in strings 110-1and 110-2 may be used to store m bits of data. In some examples, anm-bit memory cell might be a 2^(m)-level memory cell, where the m bitsmight be stored at one of the 2^(m) levels.

When string 110-1 and/or string 110-2 are being operated in anK-bit-per-cell (e.g., a 2^(K)-level) mode of operation, respective onesof K page buffers (e.g., page buffers 158-1 to 158-K) of page buffers158-1 to 158-N might be respectively used for respective ones ofdifferent bits of the K bits data of a K-bit memory cell, e.g., ofstring 110-1 or string 110-2. For example, respective ones of the K pagebuffers of page buffers 158-1 to 158-N might be respectively used toreceive respective ones of the K bits to be programmed to a K-bit memorycell, e.g., of string 110-1 or string 110-2, or to receive respectiveones of the K bits that are read from a K-bit memory cell, e.g., ofstring 110-1 or string 110-2.

When strings 110-1 and 110-2 are being operated in an m-bit-per-cell(e.g., a 2^(m)-level) mode of operation, respective ones of m pagebuffers of the page buffers 158-1 to 158-N might be respectively usedfor respective ones of the m bits data corresponding to a selectedmemory cell of string 110-1, and respective ones of m other (e.g., mremaining) page buffers of the page buffers 158-1 to 158-N might berespectively used for respective ones of the m bits data correspondingto a selected memory cell of string 110-2. For example, respective onesof m page buffers of the page buffers 158-1 to 158-N might berespectively used to receive respective ones of the m bits to beprogrammed to the selected memory cell of string 110-1, and respectiveones of m other page buffers of the page buffers 158-1 to 158-N might berespectively used to receive respective ones of the m bits to beprogrammed to the selected memory cell of string 110-2. For example,respective ones of m page buffers of the page buffers 158-1 to 158-Nmight be respectively used to receive respective ones of m bits readfrom the selected memory cell of string 110-1, and respective ones of mother page buffers of the page buffers 158-1 to 158-N might berespectively used to receive respective ones of m bits read from theselected memory cell of string 110-2.

Following are some examples for N=4 (four), e.g., for four page buffers158-1 to 158-4. For example, for N=K=4 (four), string 110-1 and/orstring 110-2 may be operated in a four-bit-per-cell (e.g. a2⁴-level-per-cell) mode of operation, e.g., where the memory cells instring 110-1 and/or string 110-2 are operated as four-bit memory cellsand are used to store four bits of data. For K=4 (four), for example,respective ones of page buffers 158-1 to 158-4 may be respectively usedfor respective ones of different bits of the four bits data of afour-bit memory cell, e.g., of string 110-1 or string 110-2. Forexample, respective ones of page buffers 158-1 to 158-4 might berespectively used to receive respective ones of the four bits to beprogrammed to a four-bit memory cell, e.g., of string 110-1 or string110-2, or to receive respective ones of the four bits that are read froma four-bit memory cell, e.g., of string 110-1 or string 110-2.

For N=4 (four) and K=3 (three), for example, string 110-1 and/or string110-2 may be operated in a three-bit-per-cell (e.g. a 2³-level-per-cell)mode of operation, e.g., where the memory cells in string 110-1 and/orstring 110-2 are operated as three-bit memory cells and are used tostore three bits of data. For K=3 (three), for example, respective onesof three page buffers (e.g., page buffers 158-1 to 158-3) of pagebuffers 158-1 to 158-4 may be respectively used for respective ones ofdifferent bits of the three bits data of a three-bit memory cell, e.g.,of string 110-1 or string 110-2. For example, respective ones of threepage buffers (e.g., page buffers 158-1 to 158-3) of page buffers 158-1to 158-4 might be respectively used to receive respective ones of thethree bits to be programmed to a three-bit memory cell, e.g., of string110-1 or string 110-2, or to receive respective ones of the three bitsthat are read from a three-bit memory cell, e.g., of string 110-1 orstring 110-2.

For an example where N=4 (four) and K=3 (three) or 4 (four), m might be2 (two), for example. For example, respective ones of two page buffers(e.g., page buffers 158-1 and 158-3) of the page buffers 158-1 to 158-4might be respectively used for respective ones of the two bits of datacorresponding to a selected memory cell of string 110-1, and respectiveones of two other (e.g., two remaining) page buffers (e.g., page buffers158-2 and 158-4) of the page buffers 158-1 to 158-4 might berespectively used for respective ones of the two bits of datacorresponding to a selected memory cell of string 110-2. For example,respective ones of two page buffers (e.g., page buffers 158-1 and 158-3)of the page buffers 158-1 to 158-4 might be respectively used to receiverespective ones of the two bits to be programmed to the selected memorycell of string 110-1, and respective ones of two other page buffers(e.g., page buffers 158-2 and 158-4) of the page buffers 158-1 to 158-4might be respectively used to receive respective ones of the two bits tobe programmed to the selected memory cell of string 110-2. For example,respective ones of two page buffers (e.g., page buffers 158-1 and 158-3)of the page buffers 158-1 to 158-4 might be respectively used to receiverespective ones of two bits read from the selected memory cell of string110-1, and respective ones of two other page buffers (e.g., page buffers158-2 and 158-4) of the page buffers 158-1 to 158-4 might berespectively used to receive respective ones of two bits read from theselected memory cell of string 110-2.

For an example where N=4 (four) and K=3 (three) or 4 (four), m might be1 (one), for example. For example, one page buffer (e.g., page buffer158-1) of the page buffers 158-1 to 158-4 might be used for one bit ofdata corresponding to a selected memory cell of string 110-1, and onepage buffer (e.g., page buffer 158-2) of the page buffers 158-1 to 158-4might be used for one bit of data corresponding to a selected memorycell of string 110-2. For example, one page buffer (e.g., page buffer158-1) of the page buffers 158-1 to 158-4 might be used to receive onebit of data to be programmed to the selected memory cell of string110-1, and one page buffer (e.g., page buffer 158-2) of the page buffers158-1 to 158-4 might be used to receive one bit of data to be programmedto the selected memory cell of string 110-2. For example, one pagebuffer (e.g., page buffer 158-1) of the page buffers 158-1 to 158-4might be used to receive one bit of data read from the selected memorycell of string 110-1, and one page buffer (e.g., page buffer 158-2) ofthe page buffers 158-1 to 158-4 might be used to receive one bit of dataread from the selected memory cell of string 110-2.

A portion 210-1 of the stacked, e.g., the three-dimensional, memoryarrays, in the examples of FIGS. 2 and 3 may include one or more of theblocks 126-1. For example, portion 210-1 may include a plurality of datalines 125-1. A plurality of select transistors 116-1 may be connected toeach of the plurality of data lines 125-1. Respective ones of aplurality of strings 110-1 of memory cells 112-1 may be respectivelyconnected to respective ones of the plurality of select transistors116-1 connected to each of the plurality of data lines 125-1. Forexample, each of the strings 110-1 in the examples of FIGS. 2 and 3might be a vertical string with a vertical stack of memory cells 112-1.

Respective ones of a plurality of select transistors 114-1 may berespectively connected to the respective ones of the plurality of thestrings 110-1 that may be respectively connected to the respective onesof the plurality of select transistors 116-1 connected to each of theplurality of data lines 125-1. Each of the plurality of the selecttransistors 114-1 may be commonly connected to the common source 120-1and may be commonly connected to the common select line 130-1.

Respective ones of the memory cells 112-1-1 to 112-1-M in each of theplurality of the strings 110-1 may be respectively connected torespective ones of common access lines 128-1-1 to 128-1-M. One selecttransistor 116-1 of the plurality of the select transistors 116-1connected to each of the plurality of data lines 125-1 is connected to arespective one of a plurality of select lines 132-1.

A portion 210-2 of the memory arrays shown in the examples of FIGS. 2and 3 may include one or more of the blocks 126-2. For example, portion210-2 may include a plurality of data lines 125-2. A plurality of selecttransistors 116-2 may be connected to each of the plurality of datalines 125-2. Respective ones of a plurality of the strings 110-2 ofmemory cells 112-2 may be respectively connected to respective ones ofthe plurality of select transistors 116-2 connected to each of theplurality of data lines 125-2. For example, each of the strings 110-2 inthe examples of FIGS. 2 and 3 might be a vertical string with a verticalstack of memory cells 112-2.

Respective ones of a plurality of the select transistors 114-2 may berespectively connected to the respective ones of the plurality of thestrings 110-2 that may be respectively connected to the respective onesof the plurality of select transistors 116-2 connected to each of theplurality of data lines 125-2. Each of the plurality of the selecttransistors 114-2 may be commonly connected to the common source 120-2and may be commonly connected to the common select line 130-2.

Respective ones of the memory cells 112-2-1 to 112-2-M in each of theplurality of the strings 110-2 may be respectively connected torespective ones of common access lines 128-2-1 to 128-2-M. One selecttransistor 116-2 of the plurality of the select transistors 116-2connected to each of the plurality of data lines 125-1 is connected to arespective one of a plurality of select lines 132-2.

Respective ones of the plurality of data lines 125-1 may be respectivelyconnected to respective ones of a plurality of transistors 150 that maybe respectively connected to respective ones of the plurality of datalines 125-2, as shown in the examples of FIGS. 2 and 3. For example, therespective ones of the plurality of transistors 150 may respectivelyselectively connect the respective ones of the plurality of data lines125-1 to the respective ones of the plurality of data lines 125-2. Eachof the plurality of transistors 150 may be connected to a control line152.

In the example of FIG. 2, the plurality of transistors 150 may bebetween the portions 210-1 and 210-2 and may be at a vertical level thatis below the portions 210-1 and 210-2. For example, in FIG. 2, therespective ones of the plurality of transistors 150 may be respectivelybetween the respective ones of the plurality of data lines 125-1 and therespective ones of the plurality of data lines 125-2 and may berespectively connected to ends of the respective ones of the pluralityof data lines 125-1 and the respective ones of the plurality of datalines 125-2.

In the example of FIG. 3, the plurality of transistors 150 may be under(e.g., directly vertically under) portion 210-2, e.g., at a verticallevel that is directly vertically below portion 210-2. For example, inFIG. 3, the respective ones of the plurality of transistors 150 may berespectively connected to ends of the respective ones of the pluralityof data lines 125-1. The respective ones of the plurality of transistors150 may be respectively connected to the respective ones of theplurality of data lines 125-2 somewhere between the ends of therespective ones of the plurality of data lines 125-2. For example, atransistor 150 may be connected to a respective data line 125-2 betweenwhere adjacent strings 110-2 of portion 210-2 are selectively connectedto the respective data line 125-2. For example, the adjacent strings maybe respectively in different blocks of memory cells in portion 210-2such that the transistor 150 may be connected to the respective dataline 125-2 somewhere between the different blocks of memory cells inportion 210-2.

FIG. 4 presents a timing diagram for an example of a programmingoperation, e.g., for programming the configuration of FIG. 1. Forexample, the programming operation in the example of FIG. 4 might beapplied during a single-bit-per-cell (e.g., a two-level) programmingmode for programming a target memory cell 112-1-T of the memory cells112-1-1 to 112-1-M in the string 110-1 in FIG. 1 that is targeted forprogramming, e.g., as a single-bit memory cell, and a target memory cell112-2-T of the memory cells 112-2-1 to 112-2-M in the string 110-2 inFIG. 1 that is targeted for programming, e.g., as a single-bit memorycell. The remaining memory cells of the memory cells 112-1-1 to 112-1-Min the string 110-1 are untargeted memory cells of the memory cells112-1-1 to 112-1-M in the string 110-1 and are not targeted forprogramming, and the remaining memory cells of the memory cells 112-2-1to 112-2-M in the string 110-2 are untargeted memory cells of the memorycells 112-2-1 to 112-2-M in the string 110-2 and are not targeted forprogramming. Note that the programming operation in the example of FIG.4 might be applied during an m-bit-per-cell (e.g., a 2^(m)-level)programming mode for programming the target memory cell 112-1-T, e.g.,as an m-bit memory cell, and the target memory cell 112-2-T, e.g., as anm-bit memory cell. Note that m=1 for the single-bit-per-cell programmingmode.

The control gate of the target memory cell 112-1-T is connected to aselected access line 128-1-Sel of the access lines 128-1-1 to 128-1-M,and the control gate of the target memory cell 112-2-T is connected to aselected access line 128-2-Sel of the access lines 128-2-1 to 128-2-M.The remaining access lines of the access lines 128-1-1 to 128-1-M areunselected access lines of the access lines 128-1-1 to 128-1-M and arerespectively connected to the control gates of the untargeted memorycells of the memory cells 112-1-1 to 112-1-M in the string 110-1, andthe remaining access lines of the access lines 128-2-1 to 128-2-M areunselected access lines of the access lines 128-2-1 to 128-2-M and arerespectively connected to the control gates of the untargeted memorycells of the memory cells 112-2-1 to 112-2-M in the string 110-2.

A voltage 405 may be applied to the control line 152 that is connectedto the control gate of transistor 150. Voltages 410 and 415 may berespectively applied to data lines 125-2 and 125-1. For example, forsingle-bit-per-cell programming, page buffer 158-1 might supply voltage415 to data line 125-1, e.g., in response to an address being receivedthat addresses target memory cell 112-1-T, and page buffer 158-2 mightsupply voltage 410 to data line 125-2, e.g., in response to an addressbeing received that addresses target memory cell 112-2-T. In otherexamples, for m-bit-per-cell programming, one of m page buffers (e.g.,page buffer 158-1) of page buffers 158-1 to 158-N assigned to targetmemory cell 112-1-T might supply voltage 415 to data line 125-1 and oneof m other page buffers (e.g., page buffer 158-2) of page buffers 158-1to 158-N assigned to target memory cell 112-2-T might supply voltage 410to data line 125-2.

A voltage 420 may be concurrently applied to the selected access lines128-1-Sel and 128-2-Sel, and thus to the control gates of the targetmemory cells 112-1-T and 112-2-T respectively connected to the selectedaccess lines 128-1-Sel and 128-2-Sel. A voltage 425 may be concurrentlyapplied to the unselected access lines of the access lines 128-1-1 to128-1-M, and thus to the control gates of the untargeted memory cells ofthe memory cells 112-1-1 to 112-1-M respectively connected to theunselected access lines of the access lines 128-1-1 to 128-1-M, and tothe unselected access lines of the access lines 128-2-1 to 128-2-M, andthus to the control gates of the untargeted memory cells of the memorycells 112-2-1 to 112-2-M respectively connected to the unselected accesslines of the access lines 128-2-1 to 128-2-M. A voltage 430 may beconcurrently applied to the select lines 132-1 and 132-2 respectivelyconnected to the control gates of select transistors 116-1 and 116-2.

The programming operation might commence by loading data (e.g., one bitof data for single-bit-per-cell programming) into page buffer 158-1 thatis to be programmed into target memory cell 112-1-T and data (e.g., onebit of data for single-bit-per-cell programming) into page buffer 158-2that is to be programmed into target memory cell 112-2-T. For example,data latch 160 may receive the data from I/O bus 162 and respectivelylatch the data into page buffers 158-1 and 158-2. Transistor 150 maythen be activated from a deactivated state by changing the voltage levelof the voltage 405 applied to control line 152 from a deactivationvoltage level Vdeact, such as a voltage level Vss (e.g., ground), thatcauses transistor 150 to be deactivated to an activation voltage levelVact, such as a voltage level Vcc or greater, that activates transistor150. Note, for example, that for m-bit per cell programming, theprogramming operation might commence by loading respective ones of the mbits of data to be programmed into target memory cell 112-1-T intorespective ones of the m page buffers assigned to target memory cell112-1-T and by loading respective ones of the m bits of data to beprogrammed into target memory cell 112-2-T into respective ones of the mother page buffers assigned to target memory cell 112-2-T.

The voltage 415 applied to data line 125-1 may be based on the data inpage buffer 158-1 to be programmed to target memory cell 112-1-T. Forexample, while transistor 150 is activated, the level of the voltage 415applied to data line 125-1 may be at a non-inhibit voltage levelVdLprog, such as Vss, that allows target memory cell 112-1-T to program,e.g., that allows the threshold voltage of target memory cell 112-1-T tobe changed (e.g., shifted) in the event that the threshold voltage oftarget memory cell 112-1-T might need to be changed to store the one bitof data that is in page buffer 158-1 for single-bit-per-cell programmingor to store the respective ones of the m bits of data in the respectiveones of the m page buffers assigned to target memory cell 112-1-T form-bit-per-cell programming. Transistor 150 may be subsequentlydeactivated, by changing the voltage level of the voltage 405 applied tocontrol line 152 from the voltage level Vact to the voltage levelVdeact, while the voltage 415 applied to data line 125-1 is at thevoltage level VdLprog. For example, deactivating transistor 150maintains voltage level VdLprog on data line 125-1 and electricallyisolates data line 125-1 from data line 125-2, and thus electricallyisolates data line 125-1 from page buffers 158-1 and 158-2. Note thatfor single-bit-per-cell programming, while transistor 150 is activated,page buffer 158-1 may be activated to supply voltage 415 to data line125-1 and page buffer 158-2 may be deactivated, e.g., page buffer 158-2may be deactivated while page buffer 158-1 is activated. Form-bit-per-cell programming, while transistor 150 is activated, pagebuffer 158-1 may be activated to supply voltage 415 to data line 125-1and page buffer 158-2 may be deactivated, e.g., page buffer 158-2 may bedeactivated while page buffer 158-1 is activated.

In the event that the threshold voltage of target memory cell 112-1-Tmight not need to be changed to store the bit of data that is in pagebuffer 158-1 for single-bit-per-cell programming or to store respectiveones of the m bits in the respective ones of the m page buffers assignedto target memory cell 112-1-T for m-bit-per-cell programming, whiletransistor 150 is activated, the level of the voltage 415 applied todata line 125-1 might be changed from the voltage level VdLprog to aninhibit voltage level Vinh, such as the voltage level Vcc, that inhibitsthe threshold voltage of target memory cell 112-1-T from being changed,and thus inhibits target memory cell 112-1-T from being programmed.Transistor 150 may then be deactivated while data line 125-1 is at thevoltage level Vinh, e.g., to maintain the voltage level Vinh on dataline 125-1.

Target memory cell 112-1-T may be inhibited from further programming inthe event that it programs, e.g., reaches a target threshold voltage,before other target memory cells that are connected to selected accessline 128-1-Sel. For example, program voltages might be applied toselected access line 128-1-Sel, while target memory cell 112-1-T isinhibited, until the other target memory cells that are connected toselected access line 128-1-Sel are programmed or fail to program incertain number of programming operations. Alternatively, target memorycell 112-1-T may be inhibited when target memory cell 112-1-T is at aninitial state, e.g., a lowest state, such as an erased state or a stateafter a healing operation or pre-programming operation has been appliedafter an erase, and page buffer 158-1 specifies data corresponding tothe initial state.

Note that the voltage 415 that is applied by page buffer 158-1 to dataline 125-1 while transistor 150 is activated is applied through dataline 125-2, in that data line 125-2 is between page buffer 158-1 anddata line 125-1 and is connected in series with data line 125-1 whiletransistor 150 is activated. Therefore, while transistor 150 isactivated, voltage 415 may be applied to both data lines 125-1 and 125-2concurrently, for example. For example, dashed line 411 in FIG. 4 showswhen the voltage 415 is at the voltage level Vinh, and thus both datalines 125-1 and 125-2 are at the voltage level Vinh concurrently.Deactivating page buffer 158-1 and activating page buffer 158-2 aftertransistor 150 is deactivated may cause the voltage 415 on data line125-2 to drop to the voltage level VdLprog from the voltage level Vinhin the event page buffer 158-2 applies the voltage level VdLprog levelto data line 125-2.

The voltage 415 applied to data line 125-2 while transistor 150 isactivated may be referred to as a do-not-care voltage, in that it is notintended to be used during the programming of the memory cells 112-2-1to 112-2-M, such as target memory cell 112-2-T, in string 110-2selectively connected to data line 125-2. That is, for example, voltage415 is based on the data to be programmed to target memory cell 112-1-Tin string 110-1 selectively connected to data line 125-1. For example,the voltage 415 applied to data line 125-2 may be superseded by thevoltage 410 that may be applied to data line 125-2 by page buffer 158-2while transistor 150 is deactivated and that may be based on the data inpage buffer 158-2 to be programmed to target memory cell 112-2-T instring 110-2 selectively connected to data line 125-2.

After transistor 150 is deactivated by changing the voltage level of thevoltage 405 applied to control line 152 from the voltage level Vact tothe voltage level Vdeact, and thus data line 125-1 is electricallyisolated from data line 125-2 and from page buffers 158-1 and 158-2 forsingle-bit-per-cell programming or from page buffers 158-1 to 158-N form-bit-per-cell programming, and the voltage 415 on data line 125-1 iseither at the voltage level VdLprog or the voltage level Vinh, thevoltage 410 applied to data line 125-2 may be left at the non-inhibitvoltage level VdLprog that allows target memory cell 112-2-T to program,e.g., that allows the threshold voltage of target memory cell 112-2-T tobe changed (e.g., shifted) in the event that the threshold voltage oftarget memory cell 112-2-T might need to be changed to store the bit ofdata that is in page buffer 158-2 for single-bit-per-cell programming orto store respective ones of the m bits of data in the respective ones ofthe m page buffers assigned to target memory cell 112-2-T form-bit-per-cell programming.

In the event that the threshold voltage of target memory cell 112-2-Tmight not need to be changed to store the bit of data that is in pagebuffer 158-2 for single-bit-per-cell programming or to store respectiveones of the m bits of data in the respective ones of the m page buffersassigned to target memory cell 112-2-T for m-bit-per-cell programming,after transistor 150 is deactivated, the level of the voltage 410applied to data line 125-2 might be changed from the voltage levelVdLprog to inhibit voltage level Vinh that inhibits the thresholdvoltage of target memory cell 112-2-T from being changed, and thusinhibits target memory cell 112-2-T from being programmed. Note thatwhile transistor 150 is deactivated, page buffer 158-2 may be activatedto supply the voltage 410 to data line 125-2 and page buffer 158-1 maybe deactivated, e.g., page buffer 158-1 may be deactivated while pagebuffer 158-2 is activated.

Target memory cell 112-2-T may be inhibited from further programming inthe event that it programs, e.g., reaches a target threshold voltage,before other target memory cells that are connected to selected accessline 128-2-Sel. For example, program voltages might be applied toselected access line 128-2-Sel, while target memory cell 112-2-T isinhibited, until the other target memory cells that are connected toselected access line 128-2-Sel are programmed or fail to program incertain number of programming operations. Alternatively, target memorycell 112-2-T may be inhibited when target memory cell 112-2-T is at aninitial state, e.g., a lowest state, such as an erased state or a stateafter a healing operation or pre-programming operation has been appliedafter an erase, and page buffer 158-2 specifies the bit of datacorresponding to the initial state for single-bit-per-cell programmingor the respective ones of the m page buffers assigned to target memorycell 112-2-T respectively specify the respective ones of the m bits ofdata corresponding to the initial state for m-bit-per-cell programming.

While the voltage 415 on data line 125-1 is either at the voltage levelVdLprog or the voltage level Vinh and while the voltage 410 applied todata line 125-2 is either at the voltage level VdLprog or the voltagelevel Vinh, select transistors 116-1 and 116-2 may be concurrentlyactivated from deactivated states by changing the voltage level of thevoltage 430 concurrently applied to the select lines 132-1 and 132-2respectively connected to select transistors 116-1 and 116-2 from thedeactivation voltage level Vdeact that causes select transistors 116-1and 116-2 to be deactivated to the activation voltage level Vact thatmay concurrently activate select transistors 116-1 and 116-2. While thevoltage level of the voltage 430 is increased (e.g., concurrently withincreasing the voltage level of the voltage 430) from the voltage levelVdeact to the voltage level Vact, the voltage 420 concurrently appliedto the selected access lines 128-1-Sel and 128-2-Sel and the voltage 425concurrently applied to the unselected access lines of the access lines128-1-1 to 128-1-M and the unselected access lines of the access lines128-2-1 to 128-2-M are concurrently increased from a voltage level Vlow,such as Vss, to a pass voltage level, such as voltage level Vpass-prog.

The voltage 420 concurrently applied to the selected access lines128-1-Sel and 128-2-Sel is subsequently increased from the voltage levelVpass-prog to a program voltage level, such as voltage level Vprog,while select transistors 116-1 and 116-2 are activated, while thevoltage 425 concurrently applied to the unselected access lines of theaccess lines 128-1-1 to 128-1-M and the unselected access lines of theaccess lines 128-2-1 to 128-2-M remains at the voltage level Vpass-prog,and while the voltage 415 on data line 125-1 is either at the voltagelevel VdLprog or the voltage level Vinh and the voltage 410 applied todata line 125-2 is either at the voltage level VdLprog or the voltagelevel Vinh.

In some examples, while select transistors 116-1 and 116-2 are activatedand data lines 125-1 and 125-2 are at the voltage level VdLprog, thevoltage level VdLprog may be transferred to the channels of targetmemory cells 112-1-T and 112-2-T while the selected access lines128-1-Sel and 128-2-Sel, and thus the control gates of target memorycells 112-1-T and 112-2-T, are at the voltage level Vprog. Thedifference between the voltage level Vprog on the control gates oftarget memory cells 112-1-T and 112-2-T and the voltage level VdLprog onthe channels of target memory cells 112-1-T and 112-2-T, for example,may be sufficient to cause target memory cells 112-1-T and 112-2-T toprogram, e.g., may be sufficient to cause a shift in the thresholdvoltages of target memory cells 112-1-T and 112-2-T.

In some examples, while the data line 125-1 is at the voltage level Vinhand while the voltage level Vact is applied to select transistor 116-1so that transistor 116-1 is activated and connects the data line 125-1that is at the voltage level Vinh to a channel of target memory cell112-1-T, voltage might be transferred from data line 125-1 to thechannel of target memory cell 112-1-T until select transistor 116-1becomes deactivated, while the voltage level Vact is applied to selecttransistor 116-1. Similarly, for example, while the data line 125-2 isat the voltage level Vinh and while the voltage level Vact is applied toselect transistor 116-2 so that transistor 116-2 is activated andconnects the data line 125-2 that is at the voltage level Vinh to achannel of target memory cell 112-2-T, voltage might be transferred fromdata line 125-2 to the channel of target memory cell 112-2-T untilselect transistor 116-2 becomes deactivated, while the voltage levelVact is applied to select transistor 116-2. While select transistors116-1 and 116-2 are deactivated in this manner, for example, the voltagelevel Vpass-prog applied to the unselected access lines of the accesslines 128-1-1 to 128-1-M, the unselected access lines of the accesslines 128-2-1 to 128-2-M, and the selected access lines 128-1-Sel and128-2-Sel and the voltage level Vprog that is subsequently applied tothe selected access lines 128-1-Sel and 128-2-Sel act to boost thevoltage on the channels of target memory cells 112-1-T and 112-2-T tolevels where the difference between the voltage on the channels oftarget memory cells 112-1-T and 112-2-T and the voltage level Vprogapplied to the selected access lines 128-1-Sel and 128-2-Sel, and thusto the control gates of target memory cells 112-1-T and 112-2-T, may beinsufficient to cause target memory cells 112-1-T and 112-2-T toprogram, e.g., may be insufficient to cause a shift in the thresholdvoltages of target memory cells 112-1-T and 112-2-T, and thus targetmemory cells 112-1-T and 112-2-T may be inhibited from being programmed.

After the voltage level Vprog is concurrently applied to the selectedaccess lines 128-1-Sel and 128-2-Sel, the target memory cells 112-1-Tand 112-2-T respectively connected to selected access lines 128-1-Seland 128-2-Sel may be sensed by applying a program verify voltage to theselected access lines 128-1-Sel and 128-2-Sel during a program verifyoperation to determine whether target memory cells 112-1-T and 112-2-Thave been respectively programmed to the data values in page buffers158-1 and 158-2. When it is determined that the target memory cells112-1-T and 112-2-T are not programmed to the data values in pagebuffers 158-1 and 158-2, the voltage level Vprog concurrently applied tothe selected access lines 128-1-Sel and 128-2-Sel may be incremented bya step voltage. The target memory cells 112-1-T and 112-2-T may then besensed with the program verify voltage to determine whether targetmemory cells 112-1-T and 112-2-T have been respectively programmed tothe respective bits of data respectively in page buffers 158-1 and 158-2for single-bit-per-cell programming or, for m-bit-per-cell-programming,target memory cell 112-1-T is programmed to the m bits in the m pagebuffers, of the page buffers 158-1 and 158-N, assigned to target memorycell 112-1-T and target memory cell 112-2-T is programmed to the m bitsin the m page buffers, of the page buffers 158-1 and 158-N, assigned totarget memory cell 112-2-T. The program voltage level may continue to beincremented and target memory cells 112-1-T and 112-2-T may continue tobe sensed until it is verified that target memory cells 112-1-T and112-2-T are respectively programmed to the respective bits of datarespectively in page buffers 158-1 and 158-2 for single-bit-per-cellprogramming or, for m-bit-per-cell-programming, target memory cell112-1-T is programmed to the m bits in the m page buffers assigned totarget memory cell 112-1-T and target memory cell 112-2-T is programmedto the m bits in the m page buffers assigned to target memory cell112-2-T, or until the target memory cells 112-1-T and 112-2-T fail toverify in a certain number of program/program verify operations.

FIG. 5 presents a timing diagram for an example of a sensing operation,e.g., during a single-bit-per cell (e.g., a two-level) sensing mode,that senses the target memory cell 112-1-T of the memory cells 112-1-1to 112-1-M in the string 110-1 in FIG. 1 when targeted for sensing,e.g., as a single-bit memory cell, and the target memory cell 112-2-T ofthe memory cells 112-2-1 to 112-2-M in the string 110-2 in FIG. 1 whentargeted for sensing, e.g., as a single-bit memory cell. The remainingmemory cells of the memory cells 112-1-1 to 112-1-M in the string 110-1are untargeted memory cells of the memory cells 112-1-1 to 112-1-M inthe string 110-1 and are not targeted for sensing, and the remainingmemory cells of the memory cells 112-2-1 to 112-2-M in the string 110-2are untargeted memory cells of the memory cells 112-2-1 to 112-2-M inthe string 110-2 and are not targeted for sensing. Note that the sensingoperation in the example of FIG. 5 might be applied during anm-bit-per-cell (e.g., a 2^(m)-level) sensing mode for sensing targetmemory cell 112-1-T, e.g., as an m-bit memory cell, and target memorycell 112-2-T, e.g., as an m-bit memory cell. Note that m=1 for thesingle-bit-per-cell sensing mode.

The sensing operation, for example, might be a program verify operationthat may be performed to determine whether the target memory cells112-1-T and 112-2-T have programmed, e.g., reached at least a targetthreshold voltage, in response to a program voltage being applied to theselected access lines 128-1-Sel and 128-2-Sel respectively connected totarget memory cells 112-1-T and 112-2-T. Alternatively, the sensingoperation, for example, might be a read operation performed on thetarget memory cells 112-1-T and 112-2-T.

A voltage 505 may be applied to the control line 152 that is connectedto the control gate of transistor 150. A voltage 510 may be concurrentlyapplied to data lines 125-1 and 125-2, e.g., from sense amplifier 155 orone of the page buffers 158-1 or 158-2 when transistor 150 is activatedto connect data lines 125-1 and 125-2 in series. For example, voltage510 may only be applied to data line 125-2 before transistor 150 isactivated, and when transistor 150 is activated to connect data lines125-1 and 125-2 in series, voltage 510 is applied to data line 125-1through data line 125-2 so that voltage 510 is concurrently applied todata lines 125-1 and 125-2. That is, for example, FIG. 5 shows voltage510 concurrently applied to data lines 125-1 and 125-2.

A voltage 520 may be concurrently applied to the selected access lines128-1-Sel and 128-2-Sel respectively connected to the control gates oftarget memory cells 112-1-T and 112-2-T. A voltage 525 may beconcurrently applied to the unselected access lines of the access lines128-1-1 to 128-1-M respectively connected to the control gates of theuntargeted memory cells of the memory cells 112-1-1 to 112-1-M and theunselected access lines of the access lines 128-2-1 to 128-2-Mrespectively connected to the control gates of the untargeted memorycells of the memory cells 112-2-1 to 112-2-M. A voltage 530 may beconcurrently applied to select line 130-1 connected to the control gateof select transistor 114-1 and to select line 132-1 connected to thecontrol gate of select transistor 116-1, and a voltage 535 may beconcurrently applied to select line 130-2 connected to the control gateof select transistor 114-2 and to select line 132-2 connected to thecontrol gate of select transistor 116-2. In some examples, sources 120-1and 120-2 might be grounded during the sensing operation.

The sensing operation might commence by increasing the level of voltage520 to a sense voltage level and the level of the voltage 525 to a passvoltage level. For example, the level of voltage 520 concurrentlyapplied to the selected access lines 128-1-Sel and 128-2-Sel, and thusto the control gates of target memory cells 112-1-T and 112-2-T, may beincreased from a voltage level Vlow, such as Vss, to a sense voltagelevel Vsense, such as a read voltage when the sensing operation is aread operation or a program verify voltage when the sensing operation isa program verify operation.

The level of the voltage 525 concurrently applied to the unselectedaccess lines of the access lines 128-1-1 to 128-1-M, and thus to thecontrol gates of the untargeted memory cells of the memory cells 112-1-1to 112-1-M, and to the unselected access lines of the access lines128-2-1 to 128-2-M, and thus to the control gates of the untargetedmemory cells of the memory cells 112-2-1 to 112-2-M, for example, may beincreased from the voltage level Vlow to a voltage level Vpass-sensethat is sufficient to activate the untargeted memory cells of the memorycells 112-1-1 to 112-1-M respectively connected to the unselected accesslines of the access lines 128-1-1 to 128-1-M and the untargeted memorycells of the memory cells 112-2-1 to 112-2-M respectively connected tothe unselected access lines of the access lines 128-2-1 to 128-2-M. Thatis, for example, the activated untargeted memory cells may pass current.Voltage 520 may remain at sense voltage level Vsense during the senseoperation, and voltage 525 may remain at voltage level Vpass-senseduring the sense operation. That is, for example, the unselected accesslines of the access lines 128-1-1 to 128-1-M and the unselected accesslines of the access lines 128-2-1 to 128-2-M may be at voltage levelVpass-sense while the selected access lines 128-1-Sel and 128-2-Sel areat voltage level Vsense.

While voltage 520 is at sense voltage level Vsense and voltage 525 is atvoltage level Vpass-sense, transistor 150 may then be activated from adeactivated state by changing the voltage level of the voltage 505applied to control line 152 from the deactivation voltage level Vdeactto the activation voltage level Vact. Transistor 150 may remainactivated during the sensing operation, for example. That is, forexample, transistor 150 may remain activated while the unselected accesslines of the access lines 128-1-1 to 128-1-M and the unselected accesslines of the access lines 128-2-1 to 128-2-M are at voltage levelVpass-sense and while the selected access lines 128-1-Sel and 128-2-Selare at voltage level Vsense. Note that, when transistor 150 isactivated, data lines 125-1 and 125-2 are connected in series.

When transistor 150 is activated, voltage 510 is concurrently applied todata lines 125-1 and 125-2 that are connected in series by activatedtransistor 150. While transistor 150 is activated and while voltage 520is at sense voltage level Vsense and the level of the voltage 525 is atvoltage level Vpass-sense, the voltage 510 concurrently applied to datalines 125-1 and 125-2 may be increased from a voltage level Vlow, suchas Vss, to a voltage level Vchg. Subsequently, while voltage 520 is atsense voltage level Vsense, voltage 525 is at voltage level Vpass-sense,transistor 150 is activated, and select transistors 114-2 and 116-2 aredeactivated, select transistors 114-1 and 116-1 may be concurrentlyactivated (e.g., in response to an address being received that addressestarget memory cell 112-1-T) by increasing the voltage level of thevoltage 530 concurrently applied to the select lines 130-1 and 132-1from the deactivation voltage level Vdeact to the activation voltagelevel Vact. Activating select transistor 114-1 may connect string 110-1,and thus target memory cell 112-1-T, to source 120-1, and activatingselect transistor 116-1 may connect string 110-1, and thus target memorycell 112-1-T, to data line 125-1, and thus to data line 125-2. Theaddress that addresses target memory cell 112-1-T, for example, maycause a data value corresponding to the sensed state of target memorycell 112-1-T to be stored in page buffer 158-1.

Note that select transistors 114-2 and 116-2 are deactivated when thevoltage 535 concurrently applied to the select lines 130-2 and 132-2that are respectively connected to select transistors 114-2 and 116-2 isat the voltage level Vdeact so that string 110-2, and thus target memorycell 112-2-T, is disconnected from source 120-2 and data line 125-2, andthus data line 125-1. That is, for example, when select transistor 116-2is deactivated, string 110-2, and thus target memory cell 112-2-T, isdisconnected from sense amplifier 155 and page buffers 158-1 and 158-2.

When the sense voltage level Vsense applied to selected access line128-1-Sel is insufficient to activate the target memory cell 112-1-T, acurrent might not be able to flow through the series-connected datalines 125-1 and 125-2 and through the string 110-1 that includes targetmemory cell 112-1-T. As such, for example, sense amplifier 155 might notsense a current on the series-connected data lines 125-1 and 125-2, andthus data lines 125-1 and 125-2 may remain at the voltage level Vchg.For example, sense amplifier 155 might sense the voltage level Vchg ondata lines 125-1 and 125-2 when target memory cell 112-1-T remainsdeactivated in response to the sense voltage level Vsense being appliedto selected access line 128-1-Sel.

When the sense voltage level Vsense applied to selected access line128-1-Sel is sufficient to activate the target memory cell 112-1-T,current may flow through the series-connected data lines 125-1 and 125-2and through the string 110-1 that includes target memory cell 112-1-T tosource 120-1, for example. As such, for example, sense amplifier 155might sense a current flow on the series-connected data lines 125-1 and125-2. The current flow might cause the level of the voltage 510 todecrease from the voltage level Vchg to a voltage level the voltagelevel Vdchg while the voltage 530 is at the voltage level Vact andselect transistors 130-1 and 132-1 are activated. For example, senseamplifier 155 might sense the voltage level Vdchg on data lines 125-1and 125-2 when target memory cell 112-1-T is activated in response tothe sense voltage level Vsense being applied to selected access line128-1-Sel.

Sense amplifier 155 not detecting a current flow and/or sense amplifier155 detecting the voltage level Vchg, may be indicative of the thresholdvoltage of target memory cell 112-1-T being greater than the sensevoltage level Vsense. For example, when sense voltage level Vsense is aprogram verify voltage during a program verify operation, senseamplifier 155 not detecting a current flow and/or sense amplifier 155detecting the voltage level Vchg may be indicative of target memory cell112-1-T being programmed to a desired data state, e.g., target memorycell 112-1-T passing the program verify operation, and a data value inpage buffer 158-1 might be changed, e.g., to a logical one (1), toindicate that target memory cell 112-1-T is programmed.

When sense voltage level Vsense is a read voltage during a readoperation for a single-bit-per-cell read operation, for example, senseamplifier 155 not detecting a current flow and/or sense amplifier 155detecting the voltage level Vchg may be indicative of target memory cell112-1-T having a threshold voltage corresponding (e.g., assigned) to aparticular data value, such as a logical 1, and thus may be indicativeof target memory cell 112-1-T storing a logical 1. For example, the readoperation may read the logical 1 stored on target memory cell 112-1-T.For example, the logical 1 might be stored in page buffer 158-1 and besubsequently latched by data latch 160 to I/O bus 162. Note, forexample, that page buffer 158-1 may be used in response to an addressbeing received that addresses target memory cell 112-1-T.

Sense amplifier 155 detecting a current flow and/or sense amplifier 155detecting the voltage level Vdchg, may be indicative of the thresholdvoltage of target memory cell 112-1-T being less than the sense voltagelevel Vsense. For example, when sense voltage level Vsense is theprogram verify voltage during the program verify operation, senseamplifier 155 detecting a current flow and/or sense amplifier 155detecting the voltage level Vdchg may be indicative of target memorycell 112-1-T not being programmed to a desired data state, e.g.,indicative of target memory cell 112-1-T failing the program verifyoperation, and a data value in page buffer 158-1 might be leftunchanged, e.g., at a logical zero (0), to indicate that target memorycell 112-1-T is not programmed. For example, logical 0 might indicatethat an increased program voltage might need to be applied to targetmemory cell 112-1-T.

When sense voltage level Vsense is a read voltage for asingle-bit-per-cell read operation, for example, sense amplifier 155detecting a current flow and/or sense amplifier 155 detecting thevoltage level Vdchg may be indicative of target memory cell 112-1-Thaving a threshold voltage corresponding to (e.g., assigned to) adifferent particular data value, such as a logical 0, and thus may beindicative of target memory cell 112-1-T storing a logical 0. Forexample, the read operation may read the logical 0 stored on targetmemory cell 112-1-T. For example, the logical 0 might be stored in pagebuffer 158-1 and be subsequently latched by data latch 160 to I/O bus162. Note that for an m-bit-per-cell read operation, respective ones ofm-bits of data read from target memory cell 112-1-T are respectivelystored in respective ones of the m page buffers assigned to targetmemory cell 112-1-T.

While voltage 520 is at sense voltage level Vsense, voltage 525 is atvoltage level Vpass-sense, transistor 150 is activated, selecttransistors 114-1 and 116-1 may be concurrently deactivated bydecreasing the voltage level of the voltage 530 concurrently applied tothe select lines 130-1 and 132-1 from the activation voltage level Vactto the deactivation voltage level Vdeact. Subsequently, while voltage520 is at sense voltage level Vsense, voltage 525 is at voltage levelVpass-sense, transistor 150 is activated, and select transistors 114-1and 116-1 are deactivated, select transistors 114-2 and 116-2 may beconcurrently activated (e.g., in response to an address being receivedthat addresses target memory cell 112-2-T) by increasing the voltagelevel of the voltage 535 concurrently applied to the select lines 130-2and 132-2 from the deactivation voltage level Vdeact to the activationvoltage level Vact. Activating select transistor 114-2 may connectstring 110-2, and thus target memory cell 112-2-T, to source 120-2, andactivating select transistor 116-2 may connect string 110-2, and thustarget memory cell 112-2-T, to data line 125-2, and thus to data line125-1. Note that when select transistor 116-1 is deactivated, string110-1, and thus target memory cell 112-1-T, is disconnected from senseamplifier 155 and page buffers 158-1 and 158-2. The address thataddresses target memory cell 112-2-T, for example, may cause a singlebit of data corresponding to the sensed state of target memory cell112-2-T to be stored in page buffer 158-2 for single-bit-per-cellsensing or respective ones of m bits of data corresponding to the sensedstate of target memory cell 112-2-T to be respectively stored inrespective ones of the m page buffers assigned to target memory cell112-2-T for m-bit-per-cell sensing.

When the sense voltage level Vsense applied to selected access line128-2-Sel is insufficient to activate the target memory cell 112-2-T, acurrent might not be able to current to flow through theseries-connected data lines 125-1 and 125-2 and through the string 110-2that includes target memory cell 112-2-T. As such, for example, senseamplifier 155 might not sense a current on the series-connected datalines 125-1 and 125-2, and thus data lines 125-1 and 125-2 may remain atthe voltage level Vchg. For example, sense amplifier 155 might sense thevoltage level Vchg on data lines 125-1 and 125-2 when target memory cell112-2-T remains deactivated in response to the sense voltage levelVsense being applied to selected access line 128-2-Sel.

When the sense voltage level Vsense applied to selected access line128-2-Sel is sufficient to activate the target memory cell 112-2-T,current may flow through the series-connected data lines 125-1 and 125-2and through the string 110-2 that includes target memory cell 112-2-T tosource 120-2. As such, for example, sense amplifier 155 might sense acurrent flow on the series-connected data lines 125-1 and 125-2. Thecurrent flow might cause the level of the voltage 510 to decrease fromthe voltage level Vchg to the voltage level Vdchg while the voltage 535is at the voltage level Vact and the select transistors 114-2 and 116-2are activated. For example, sense amplifier 155 might sense the voltagelevel Vdchg on data lines 125-1 and 125-2 when target memory cell112-2-T is activated in response to the sense voltage level Vsense beingapplied to selected access line 128-2-Sel.

Sense amplifier 155 not detecting a current flow and/or sense amplifier155 detecting the voltage level Vchg, may be indicative of the thresholdvoltage of target memory cell 112-2-T being greater than the sensevoltage level Vsense. For example, when sense voltage level Vsense is aprogram verify voltage during a program verify operation, senseamplifier 155 not detecting a current flow and/or sense amplifier 155detecting the voltage level Vchg may be indicative of target memory cell112-2-T being programmed to a desired data state, e.g., target memorycell 112-2-T passing the program verify operation, and a data value inpage buffer 158-2 might be changed, e.g., to a logical one (1), toindicate that target memory cell 112-2-T is programmed.

When sense voltage level Vsense is a read voltage for asingle-bit-per-cell read operation, for example, sense amplifier 155 notdetecting a current flow and/or sense amplifier 155 detecting thevoltage level Vchg may be indicative of target memory cell 112-2-Thaving a threshold voltage corresponding to (e.g., assigned to) aparticular data value, such as a logical 1, and thus may be indicativeof target memory cell 112-2-T storing a logical 1. For example, the readoperation may read the logical 1 stored on target memory cell 112-2-T.For example, the logical 1 might be stored in page buffer 158-2 and besubsequently latched by data latch 160 to I/O bus 162. Note, forexample, that page buffer 158-2 may be used in response to an addressbeing received that addresses target memory cell 112-2-T.

Sense amplifier 155 detecting a current flow and/or sense amplifier 155detecting the voltage level Vdchg, may be indicative of the thresholdvoltage of target memory cell 112-2-T being less than the sense voltagelevel Vsense. For example, when sense voltage level Vsense is a programverify voltage during the program verify operation, sense amplifier 155detecting a current flow and/or sense amplifier 155 detecting thevoltage level Vdchg may be indicative of target memory cell 112-2-T notbeing programmed to a desired data state, e.g., indicative of targetmemory cell 112-2-T failing the program verify operation, and a datavalue in page buffer 158-1 might remain unchanged, e.g., at a logicalzero (0), to indicate that target memory cell 112-2-T is not programmed.For example, logical 0 might indicate that an increased program voltagemight need to be applied to target memory cell 112-2-T.

When sense voltage level Vsense is a read voltage for asingle-bit-per-cell read operation, for example, sense amplifier 155detecting a current flow and/or sense amplifier 155 detecting thevoltage level Vdchg may be indicative of target memory cell 112-2-T ofhaving a threshold voltage corresponding to (e.g., assigned to) adifferent particular data value, such as a logical 0, and thus may beindicative of target memory cell 112-2-T storing a logical 0. Forexample, the read operation may read the logical 0 stored on targetmemory cell 112-2-T. For example, the logical 0 might be stored in pagebuffer 158-2 and be subsequently latched by data latch 160 to I/O bus162. Note that for an m-bit-per-cell read operation, respective ones ofm-bits of data read from target memory cell 112-2-T are respectivelystored in respective ones of the m page buffers assigned to targetmemory cell 112-2-T.

FIG. 6 is a schematic diagram of another example of a portion of amemory array. Common numbering is used in FIGS. 1 and 6 for similar(e.g., the same) components. For example, the commonly numberedcomponents may be as described above in conjunction with FIG. 1.

Series-connected transistors 650-1 and 650-2, such as pass transistors,may be connected between data lines 125-1 and 125-2. For example,transistor 650-1 may be connected to (e.g., in series with) data line125-1, and transistor 650-1 may be connected to (e.g., in series with)data line 125-2. Series-connected transistors 650-1 and 650-2 mayselectively electrically connect data line 125-1 to (e.g., in serieswith) data line 125-2. That is, for example, when series-connectedtransistors 650-1 and 650-2 are both (e.g., are concurrently) activated,series-connected transistors 650-1 and 650-2 electrically connect dataline 125-1 to (e.g., in series with) data line 125-2. When one oftransistors 650-1 and 650-2 is deactivated and the other one oftransistors 650-1 and 650-2 is activated, the deactivated one oftransistors 650-1 and 650-2 electrically isolates data line 125-1 fromdata line 125-2. When both of transistors 650-1 and 650-2 aredeactivated, for example, data line 125-1 is electrically isolated fromdata line 125-2. Control gates of transistors 650-1 and 650-2 may berespectively connected to control lines 652-1 and 652-2, for example.

In the example of FIG. 6, sense amplifier 155, page buffers 158-1 and158-2, and data latch 160 may be connected to a node 655 betweentransistor 650-1 and transistor 650-2, where transistor 650-1 isconnected in series between data line 125-1 and node 655 and transistor650-2 is connected in series between data line 125-2 and node 655.Transistor 650-1, for example, may selectively connect node 655 to dataline 110-1 so that transistor 650-1 selectively connects sense amplifier155, page buffers 158-1 and 158-2, and data latch 160 in parallel todata line 110-1 through node 655. Transistor 650-2, for example, mayselectively connect node 655 to data line 110-2 so that transistor 650-2selectively connects sense amplifier 155, page buffers 158-1 and 158-2,and data latch 160 in parallel to data line 110-2 through node 655.

In other examples, there might be additional page buffers, such as thepage buffers 158-3 to 153-N indicated by dashed lines in FIG. 6.Transistor 650-1, for example, may selectively connect node 655 to dataline 110-1 so that transistor 650-1 selectively connects sense amplifier155, page buffers 158-1 to 158-N, and data latch 160 in parallel to dataline 110-1 through node 655. Transistor 650-2, for example, mayselectively connect node 655 to data line 110-2 so that transistor 650-2selectively connects sense amplifier 155, page buffers 158-1 to 158-N,and data latch 160 in parallel to data line 110-2 through node 655.Note, for example, that N=2 for the examples discussed above inconjunction with page buffers 158-1 and 158-2.

In some examples, series-connected transistors 650-1 and 650-2 mayreplace each of the plurality of transistors 150 in FIG. 2. For example,the series-connected transistors 650-1 and 650-2 may be between theportions 210-1 and 210-2 in FIG. 2 and may be at a vertical level thatis below the portions 210-1 and 210-2.

In other examples, series-connected transistors 650-1 and 650-2 mayreplace each of the plurality of transistors 150 in FIG. 3. For example,the series-connected transistors 650-1 and 650-2 may be under (e.g.,directly vertically under) portion 210-2 in FIG. 3, e.g., at a verticallevel that is directly vertically below portion 210-2. For example, therespective ones of the plurality of transistors 150 in FIG. 3 that maybe respectively connected to ends of the respective ones of theplurality of data lines 125-1 and that may be respectively connected tothe respective ones of the plurality of data lines 125-2 somewherebetween the ends of the respective ones of the plurality of data lines125-2 may be replaced with respective ones of a plurality ofseries-connected transistors 650-1 and 650-2.

FIG. 7 presents a timing diagram for an example of a programmingoperation, e.g., for programming the configuration of FIG. 6. Forexample, the programming operation in the example of FIG. 7 might beapplied during a single-bit-per-cell-programming mode for programmingtarget memory cell 112-1-T of the memory cells 112-1-1 to 112-1-M in thestring 110-1 in FIG. 6 that is targeted for programming, e.g., as asingle-bit memory cell, and target memory cell 112-2-T of the memorycells 112-2-1 to 112-2-M in the string 110-2 in FIG. 6 that is targetedfor programming, e.g., as a single-bit memory cell. The remaining memorycells of the memory cells 112-1-1 to 112-1-M in the string 110-1 in FIG.6 are untargeted memory cells of the memory cells 112-1-1 to 112-1-M inthe string 110-1 and are not targeted for programming, and the remainingmemory cells of the memory cells 112-2-1 to 112-2-M in the string 110-2in FIG. 6 are untargeted memory cells of the memory cells 112-2-1 to112-2-M in the string 110-2 and are not targeted for programming. Notethat the programming operation in the example of FIG. 7 might be appliedduring an m-bit-per-cell programming mode for programming target memorycell 112-1-T as an m-bit memory cell and target memory cell 112-2-T asan m-bit memory cell. Note that m=1 for the single-bit-per-cellprogramming mode.

A voltage 702 may be applied to the control line 652-1 that is connectedto the control gate of transistor 650-1, and a voltage 705 may beapplied to the control line 652-2 that is connected to the control gateof transistor 650-2. Voltages 710 and 715 may respectively be applied todata lines 125-1 and 125-2. For example, for the single-bit-per-cellprogramming mode, page buffer 158-2 might supply voltage 715 to node655, e.g., in response to an address being received that addressestarget memory cell 112-2-T, and thus to data line 125-2 through node 655and through transistor 650-2 when transistor 650-2 is activated. Pagebuffer 158-1, for the single-bit-per-cell programming mode, for example,might supply voltage 710 to node 655, e.g., in response to an addressbeing received that addresses target memory cell 112-1-T, and thus todata line 125-1 through node 655 and through transistor 650-1 whentransistor 650-1 is activated. For the m-bit-per-cell programming mode,for example, one of m page buffers (e.g., page buffer 158-2), of pagebuffers 158-1 to 158-N, assigned to target memory cell 112-2-T mightsupply voltage 715 to node 655, e.g., in response to an address beingreceived that addresses target memory cell 112-2-T, and thus to dataline 125-2 through node 655 and through transistor 650-2 when transistor650-2 is activated. For the m-bit-per-cell programming mode, forexample, one of m other page buffers (e.g., page buffer 158-1), of pagebuffers 158-1 to 158-N, assigned to target memory cell 112-1-T mightsupply voltage 710 to node 655, e.g., in response to an address beingreceived that addresses target memory cell 112-1-T, and thus to dataline 125-1 through node 655 and through transistor 650-1 when transistor650-1 is activated.

A voltage 720 may be concurrently applied to the selected access lines128-1-Sel and 128-2-Sel, and thus to the control gates of the targetmemory cells 112-1-T and 112-2-T respectively connected to the selectedaccess lines 128-1-Sel and 128-2-Sel. A voltage 725 may be concurrentlyapplied to the unselected access lines of the access lines 128-1-1 to128-1-M, and thus the control gates of the untargeted memory cells ofthe memory cells 112-1-1 to 112-1-M respectively connected to theunselected access lines of the access lines 128-1-1 to 128-1-M, and tothe unselected access lines of the access lines 128-2-1 to 128-2-M, andthus the control gates of the untargeted memory cells of the memorycells 112-2-1 to 112-2-M respectively connected to the unselected accesslines of the access lines 128-2-1 to 128-2-M. A voltage 730 may beconcurrently applied to the select lines 132-1 and 132-2 respectivelyconnected to the control gates of select transistors 116-1 and 116-2.

The programming operation might commence by loading data (e.g., one bitof data for single-bit-per-cell programming) into page buffer 158-1 thatis to be programmed into target memory cell 112-1-T and data (e.g., onebit of data for single-bit-per-cell programming) into page buffer 158-2that is to be programmed into target memory cell 112-2-T. For example,data latch 160 may receive the data from to I/O bus 162 and respectivelylatch the data into page buffers 158-1 and 158-2. Note, for example,that for m-bit per cell programming, the programming operation mightcommence by loading respective ones of the m bits of data to beprogrammed into target memory cell 112-1-T into respective ones of the mpage buffers assigned to target memory cell 112-1-T and by loadingrespective ones of the m bits of data to be programmed into targetmemory cell 112-2-T into respective ones of the m other page buffersassigned to target memory cell 112-2-T. For example, data latch 160 mayreceive the data from to I/O bus 162 and respectively latch the m bitsof data to be programmed into target memory cell 112-1-T into respectiveones of the m page buffers assigned to target memory cell 112-1-T andthe m bits of data to be programmed into target memory cell 112-2-T intorespective ones of the m page buffers assigned to target memory cell112-2-T.

Transistor 650-2 may then be activated from a deactivated state (e.g.,while transistor 650-1 is deactivated) by changing the voltage level ofthe voltage 705 applied to control line 652-2 from the deactivationvoltage level Vdeact that may cause transistor 650-2 to be deactivatedto an activation voltage level Vact that may activate transistor 650-2.The voltage 715 may be based on the bit of data in page buffer 158-2 tobe programmed to target memory cell 112-2-T for single-bit-per-cellprogramming or on the m bits of data in the respective ones of the mpage buffers assigned to target memory cell 112-2-T that are to beprogrammed into target memory cell 112-2-T for m-bit-per-cellprogramming and may be applied to data line 125-2 through node 655 andthrough the activated transistor 650-2 by page buffer 158-2, e.g., whilepage buffer 158-2 is activated and while page buffer 158-1 isdeactivated. For example, while transistor 650-2 is activated, the levelof the voltage 715 applied to node 655, and thus to data line 125-2, maybe at a non-inhibit voltage level VdLprog that may allow target memorycell 112-2-T to program, e.g., that may allow the threshold voltage oftarget memory cell 112-2-T to be changed (e.g., shifted) in the eventthat the threshold voltage of target memory cell 112-2-T might need tobe changed to store the bit of data that is in page buffer 158-2 forsingle-bit-per-cell programming or to store the m bits of data in therespective ones of the m page buffers assigned to target memory cell112-2-T for m-bit-per-cell programming.

Transistor 650-2 may be subsequently deactivated, by changing thevoltage level of the voltage 705 applied to control line 652-2 from thevoltage level Vact to the voltage level Vdeact, while the voltage 715applied to data line 125-2 is at the voltage level VdLprog. For example,deactivating transistor 650-2 may maintain voltage level VdLprog on dataline 125-2 and may electrically isolate data line 125-2 from node 655,and thus may electrically isolate data line 125-2 from data line 125-1and page buffers 158-1 and 158-2.

In the event that the threshold voltage of target memory cell 112-2-Tmight not need to be changed to store the bit of data that is in pagebuffer 158-2 for single-bit-per-cell programming or to store the m bitsof data in the respective ones of the m page buffers assigned to targetmemory cell 112-2-T for m-bit-per-cell programming, while transistor650-2 is activated, the level of the voltage 715 applied to node 655,and thus to data line 125-2, might be changed from the voltage levelVdLprog to inhibit voltage level Vinh that may inhibit the thresholdvoltage of target memory cell 112-2-T from being changed, and thus mayinhibit target memory cell 112-2-T from being programmed. Transistor650-2 may then be deactivated while data line 125-2 is at the voltagelevel Vinh, e.g., to maintain the voltage level Vinh on data line 125-2.

After transistor 650-2 is deactivated and while data line 125-2 iseither at the voltage level VdLprog or voltage level Vinh, transistor650-1 may then be activated from a deactivated state by changing thevoltage level of the voltage 702 applied to control line 652-1 from thedeactivation voltage level Vdeact that may cause transistor 650-1 to bedeactivated to an activation voltage level Vact that may activatetransistor 650-1. The voltage 710 may be based on the bit of data inpage buffer 158-1 to be programmed to target memory cell 112-1-T forsingle-bit-per-cell programming or on the m bits of data in therespective ones of the m page buffers assigned to target memory cell112-1-T that are to be programmed into target memory cell 112-1-T form-bit-per-cell programming and may be applied to node 655, and thus todata line 125-1 through node 655 and through the activated transistor650-1, by page buffer 158-1, e.g., while page buffer 158-1 is activatedand while page buffer 158-2 is deactivated. For example, whiletransistor 650-1 is activated, transistor 650-2 is deactivated, and thevoltage 715 on data line 125-2 is either at the voltage level VdLprog orthe voltage level Vinh, the voltage 710 may be left at the non-inhibitvoltage level VdLprog that may allow target memory cell 112-1-T toprogram, e.g., that may allow the threshold voltage of target memorycell 112-1-T to be changed (e.g., shifted) in the event that thethreshold voltage of target memory cell 112-1-T might need to be changedto store the bit of data that is in page buffer 158-1 forsingle-bit-per-cell programming or to store the m bits of data in therespective ones of the m page buffers assigned to target memory cell112-1-T for m-bit-per-cell programming.

In the event that the threshold voltage of target memory cell 112-1-Tmight not need to be changed to store the bit of data that is in pagebuffer 158-1 for single-bit-per-cell programming or to store the m bitsof data in the respective ones of the m page buffers assigned to targetmemory cell 112-1-T for m-bit-per-cell programming, while transistor650-2 is deactivated and the voltage 715 on data line 125-2 is either atthe voltage level VdLprog or the voltage level Vinh, the level of thevoltage 710 might be changed from the voltage level VdLprog to inhibitvoltage level Vinh that may inhibit the threshold voltage of targetmemory cell 112-1-T being changed, and thus may inhibit target memorycell 112-1-T from being programmed.

While the voltage 715 on data line 125-2 is either at the voltage levelVdLprog or the voltage level Vinh and while the voltage 710 applied todata line 125-1, e.g., through node 655 and through activated transistor650-1, is either at the voltage level VdLprog or the voltage level Vinh,select transistors 116-1 and 116-2 may be concurrently activated fromdeactivated states by changing the voltage level of the voltage 730concurrently applied to the select lines 132-1 and 132-2 respectivelyconnected to select transistors 116-1 and 116-2 from the deactivationvoltage level Vdeact that may cause select transistors 116-1 and 116-2to be deactivated to the activation voltage level Vact that mayconcurrently activate select transistors 116-1 and 116-2. While thevoltage level of the voltage 730 is increased (e.g., concurrently withincreasing the voltage level of the voltage 730) from the voltage levelVdeact to the voltage level Vact, the voltage 720 concurrently appliedto the selected access lines 128-1-Sel and 128-2-Sel and the voltage 725concurrently applied to the unselected access lines of the access lines128-1-1 to 128-1-M and the unselected access lines of the access lines128-2-1 to 128-2-M are concurrently increased from a voltage level Vlowto a pass voltage level, such as voltage level Vpass-prog.

The voltage 720 concurrently applied to the selected access lines128-1-Sel and 128-2-Sel is subsequently increased from the voltage levelVpass-prog to a program voltage level, such as voltage level Vprog,while select transistors 116-1 and 116-2 are activated, while thevoltage 725 concurrently applied to the unselected access lines of theaccess lines 128-1-1 to 128-1-M and the unselected access lines of theaccess lines 128-2-1 to 128-2-M remains at the voltage level Vpass-prog,and while the voltage 715 on data line 125-2 is either at the voltagelevel VdLprog or the voltage level Vinh and the voltage 710 applied todata line 125-1 is either at the voltage level VdLprog or the voltagelevel Vinh.

A sensing operation for the example of FIG. 6, e.g., during asingle-bit-per-cell sensing mode, that senses the target memory cell112-1-T in the string 110-1 in FIG. 6, e.g., as a single-bit memorycell, and the target memory cell 112-2-T in the string 110-2 in FIG. 6,e.g., as a single-bit memory cell, may be described, for example, withreference to the example of FIG. 5. The sensing operation, for example,might be a program verify operation that may be performed to determinewhether the target memory cells 112-1-T and 112-2-T have programmed,e.g., reached at least a target threshold voltage, in response to aprogram voltage being applied to the selected access lines 128-1-Sel and128-2-Sel respectively connected to target memory cells 112-1-T and112-2-T. Alternatively, the sensing operation, for example, might be aread operation performed on the target memory cells 112-1-T and 112-2-T.A sensing operation for the example of FIG. 6 might sense the targetmemory cell 112-1-T as an m-bit memory cell and the target memory cell112-2-T an m-bit memory cell for an m-bit-per-cell sensing mode, and maybe described, for example, with reference to the example of FIG. 5.

For the example of FIG. 6, the voltage 520 in FIG. 5 may be concurrentlyapplied, e.g., in the manner described above in conjunction with FIGS. 1and 5, to the selected access lines 128-1-Sel and 128-2-Sel respectivelyconnected to the control gates of target memory cells 112-1-T and112-2-T. For the example of FIG. 6, the voltage 525 in FIG. 5 may beconcurrently applied, e.g., in the manner described above in conjunctionwith FIGS. 1 and 5, to the unselected access lines of the access lines128-1-1 to 128-1-M respectively connected to the control gates of theuntargeted memory cells of the memory cells 112-1-1 to 112-1-M and theunselected access lines of the access lines 128-2-1 to 128-2-Mrespectively connected to the control gates of the untargeted memorycells of the memory cells 112-2-1 to 112-2-M.

The sensing operation for the example of FIG. 6 might commence byincreasing the level of voltage 520 to a sense voltage level and thelevel of the voltage 525 to a pass voltage level. For example, the levelof voltage 520 concurrently applied to the selected access lines128-1-Sel and 128-2-Sel, and thus to the control gates of target memorycells 112-1-T and 112-2-T, may be increased from the voltage level Vlowto the sense voltage level Vsense, such as a read voltage when thesensing operation is a read operation or a program verify voltage whenthe sensing operation is a program verify operation.

The level of the voltage 525 concurrently applied to the unselectedaccess lines of the access lines 128-1-1 to 128-1-M, and thus to thecontrol gates of the untargeted memory cells of the memory cells 112-1-1to 112-1-M, and to the unselected access lines of the access lines128-2-1 to 128-2-M, and thus to the control gates of the untargetedmemory cells of the memory cells 112-2-1 to 112-2-M, for example, may beincreased from the voltage level Vlow to the voltage level Vpass-sensethat may be sufficient to activate the untargeted memory cells of thememory cells 112-1-1 to 112-1-M respectively connected to unselectedaccess lines of the access lines 128-1-1 to 128-1-M and the untargetedmemory cells of the memory cells 112-2-1 to 112-2-M respectivelyconnected to the unselected access lines of the access lines 128-2-1 to128-2-M. Voltage 520 may remain at sense voltage level Vsense during thesense operation; voltage 525 may remain at voltage level Vpass-senseduring the sense operation; and sources 120-1 and 120-2 may be groundedduring the sensing operation.

The voltage 505 in FIG. 5 may be applied concurrently to the controllines 652-1 and 652-2, and thus to the control gates of transistors650-1 and 650-2 in FIG. 6. For example, while voltage 520 is at sensevoltage level Vsense and voltage 525 is at voltage level Vpass-sense,transistors 650-1 and 650-2 may then be activated from a deactivatedstate by changing the voltage level of the voltage 505 applied tocontrol lines 652-1 and 652-2 from the deactivation voltage level Vdeactto the activation voltage level Vact. Transistors 650-1 and 650-2 mayremain activated during the sensing operation, for example. That is, forexample, transistors 650-1 and 650-2 may remain activated while theunselected access lines of the access lines 128-1-1 to 128-1-M and theunselected access lines of the access lines 128-2-1 to 128-2-M are atvoltage level Vpass-sense and while the selected access lines 128-1-Seland 128-2-Sel are at voltage level Vsense.

For the example of FIG. 6, the voltage 510 in FIG. 5 may be concurrentlyapplied to data lines 125-1 and 125-2, e.g., from sense amplifier 155 orone of the page buffers 158-1 or 158-2 through node 655 and throughtransistors 650-1 and 650-2 when transistors 650-1 and 650-2 areactivated concurrently, thus allowing data lines 125-1 and 125-2 toreceive voltage 510 concurrently. For example, concurrently activatedtransistors 650-1 and 650-2 may connect node 655 to data lines 125-1 and125-2 so that data lines 125-1 and 125-2 are connected in parallel tosense amplifier 155, page buffers 158-1 or 158-2 for single-bit-per-cellsensing or page buffers 158-1 to 158-N for m-bit-per-cell sensing, anddata latch 160.

Voltage 510, for example, may be applied to node 655, but may not beapplied to data lines 125-1 and 125-2 in the example of FIG. 6 beforetransistors 650-1 and 615-2 are activated. While transistors 650-1 and650-2 are activated and while voltage 520 is at sense voltage levelVsense and the level of the voltage 525 is at voltage level Vpass-sense,the voltage 510 applied to node 655, and thus concurrently applied todata lines 125-1 and 125-2, may be increased from the voltage level Vlowto the voltage level Vchg.

For the example of FIG. 6, the voltage 530 in FIG. 5 may be concurrentlyapplied, e.g., in the manner described above in conjunction with FIGS. 1and 5, to select line 130-1 connected to the control gate of selecttransistor 114-1 and to select line 132-1 connected to the control gateof select transistor 116-1, and the voltage 535 in FIG. 5 may beconcurrently applied, e.g., in the manner described above in conjunctionwith FIGS. 1 and 5, to select line 130-2 connected to the control gateof select transistor 114-2 and to select line 132-2 connected to thecontrol gate of select transistor 116-2. For example, while voltage 520is at sense voltage level Vsense, voltage 525 is at voltage levelVpass-sense, transistors 650-1 and 650-2 are activated, and selecttransistors 114-2 and 116-2 are deactivated, select transistors 114-1and 116-1 may be concurrently activated (e.g., in response to an addressbeing received that addresses target memory cell 112-1-T) by increasingthe voltage level of the voltage 530 concurrently applied to the selectlines 130-1 and 132-1 from the deactivation voltage level Vdeact to theactivation voltage level Vact.

Activating select transistor 114-1 may connect string 110-1, and thustarget memory cell 112-1-T, to source 120-1, and activating selecttransistor 116-1 may connect string 110-1, and thus target memory cell112-1-T, to data line 125-1. The activated transistors 650-1 and 650-2may connect data lines 125-1 and 125-2 to node 655, and thus to senseamplifier 155 and page buffers 158-1 and 158-2 through node 655. Theaddress that addresses target memory cell 112-1-T, for example, maycause a data value corresponding to the sensed state of target memorycell 112-1-T to be stored in page buffer 158-1.

Note that select transistors 114-2 and 116-2 may be deactivated when thevoltage 535 concurrently applied to the select lines 130-2 and 132-2that are respectively connected to select transistors 114-2 and 116-2 isat the voltage level Vdeact so that string 110-2, and thus target memorycell 112-2-T, is disconnected from source 120-2 and data line 125-2, andthus node 655 and data line 125-1. That is, for example, when selecttransistor 116-2 is deactivated, string 110-2, and thus target memorycell 112-2-T, is disconnected from sense amplifier 155 and page buffers158-1 and 158-2 for single-bit-per-cell sensing or page buffers 158-1 to158-N for m-bit-per-cell sensing.

When the sense voltage level Vsense applied to selected access line128-1-Sel is insufficient to activate the target memory cell 112-1-T, acurrent might not be able to flow through node 655, data lines 125-1 and125-2, and the string 110-1 that includes target memory cell 112-1-T. Assuch, for example, sense amplifier 155 might not sense a current at node655, and thus on data line 125-1, and thus data lines 125-1 and 125-2may remain at the voltage level Vchg. For example, sense amplifier 155might sense the voltage level Vchg on node 655, and thus data lines125-1 and 125-2, when target memory cell 112-1-T remains deactivated inresponse to the sense voltage level Vsense being applied to selectedaccess line 128-1-Sel.

When the sense voltage level Vsense applied to selected access line128-1-Sel is sufficient to activate the target memory cell 112-1-T,current may flow through node 655, the data lines 125-1 and 125-2, andthe string 110-1 that includes target memory cell 112-1-T to source120-1, for example. As such, for example, sense amplifier 155 mightsense a current flow at node 655, and thus on the data lines 125-1 and125-2. The current flow might cause the level of the voltage 510 todecrease from the voltage level Vchg to the voltage level the voltagelevel Vdchg while the voltage 530 is at the voltage level Vact and theselect transistors 114-1 and 116-1 are activated. For example, senseamplifier 155 might sense the voltage level Vdchg on node 655, and thuson data lines 125-1 and 125-2, when target memory cell 112-1-T isactivated in response to the sense voltage level Vsense being applied toselected access line 128-1-Sel.

Subsequently, select transistors 114-1 and 116-1 may be concurrentlydeactivated by decreasing the voltage level of the voltage 530concurrently applied to the select lines 130-1 and 132-1 from theactivation voltage level Vact to the deactivation voltage level Vdeact.Then, for example, while voltage 520 is at sense voltage level Vsense,voltage 525 is at voltage level Vpass-sense, transistors 650-1 and 650-2are activated, and select transistors 114-1 and 116-1 are deactivated,select transistors 114-2 and 116-2 may be concurrently activated (e.g.,in response to an address being received that addresses target memorycell 112-2-T) by increasing the voltage level of the voltage 535concurrently applied to the select lines 130-2 and 132-2 from thedeactivation voltage level Vdeact to the activation voltage level Vact.

Activating select transistor 114-2 may connect string 110-2, and thustarget memory cell 112-2-T, to source 120-2, and activating selecttransistor 116-2 may connect string 110-2, and thus target memory cell112-2-T, to data line 125-2. The activated transistors 650-1 and 650-2may connect data lines 125-1 and 125-2 to node 655, and thus to senseamplifier 155 and page buffers 158-1 and 158-2 for single-bit-per-cellsensing or page buffers 158-1 to 158-N for m-bit-per-cell sensingthrough node 655. The address that addresses target memory cell 112-2-T,for example, may cause a single bit of data corresponding to the sensedstate of target memory cell 112-1-T to be stored in page buffer 158-2for single-bit-per-cell sensing or respective ones m bits of datacorresponding to the sensed state of target memory cell 112-1-T to berespectively stored in respective ones of the m page buffers assigned totarget memory cell 112-1-T for m-bit-per-cell sensing.

Note that select transistors 114-1 and 116-1 may be deactivated when thevoltage 530 concurrently applied to the select lines 130-1 and 132-1that are respectively connected to select transistors 114-1 and 116-1 isat the voltage level Vdeact so that string 110-1, and thus target memorycell 112-1-T, is disconnected from source 120-1 and data line 125-1, andthus node 655 and data line 125-2. That is, for example, when selecttransistor 116-1 is deactivated, string 110-1, and thus target memorycell 112-1-T, is disconnected from sense amplifier 155 and page buffers158-1 and 158-2.

When the sense voltage level Vsense applied to selected access line128-2-Sel is insufficient to activate the target memory cell 112-2-T, acurrent might not be able to flow through node 655, data lines 125-1 and125-2, and the string 110-2 that includes target memory cell 112-2-T. Assuch, for example, sense amplifier 155 might not sense a current at node655, and thus on data line 125-2, and thus data lines 125-1 and 125-2may remain at the voltage level Vchg. For example, sense amplifier 155might sense the voltage level Vchg on node 655, and thus data lines125-1 and 125-2, when target memory cell 112-2-T remains deactivated inresponse to the sense voltage level Vsense being applied to selectedaccess line 128-2-Sel.

When the sense voltage level Vsense applied to selected access line128-2-Sel is sufficient to activate the target memory cell 112-2-T,current may flow through node 655, the data lines 125-1 and 125-2, andthe string 110-2 that includes target memory cell 112-2-T to source120-2, for example. As such, for example, sense amplifier 155 mightsense a current flow at node 655, and thus on the data lines 125-1 and125-2. The current flow might cause the level of the voltage 510 todecrease from the voltage level Vchg to the voltage level the voltagelevel Vdchg while the voltage 535 is at the voltage level Vact andtransistors 114-2 and 116-2 are activated. For example, sense amplifier155 might sense the voltage level Vdchg on node 655, and thus on datalines 125-1 and 125-2, when target memory cell 112-2-T is activated inresponse to the sense voltage level Vsense being applied to selectedaccess line 128-2-Sel.

Sense amplifier 155 not detecting a current flow and/or sense amplifier155 detecting the voltage level Vchg, may be indicative of the thresholdvoltage of a target memory cell being greater than the sense voltagelevel Vsense applied to the target memory cell. For example, when sensevoltage level Vsense is a program verify voltage during a program verifyoperation, sense amplifier 155 not detecting a current flow and/or senseamplifier 155 detecting the voltage level Vchg may be indicative of thetarget memory cell 112-1-T being programmed to a desired data state,e.g., the target memory cell passing the program verify operation. Whensense voltage level Vsense is a read voltage during a read operation,for example, sense amplifier 155 not detecting a current flow and/orsense amplifier 155 detecting the voltage level Vchg may be indicativeof the target memory cell having a threshold voltage corresponding to(e.g., assigned to) to a particular data value and thus may beindicative of the target memory cell storing that data value.

Sense amplifier 155 detecting a current flow and/or sense amplifier 155detecting the voltage level Vdchg, may be indicative of the thresholdvoltage of the target memory cell being less than the sense voltagelevel Vsense. For example, when sense voltage level Vsense is theprogram verify voltage during the program verify operation, senseamplifier 155 detecting a current flow and/or sense amplifier 155detecting the voltage level Vdchg may be indicative of the target memorycell not being programmed to a desired data state, e.g., the targetmemory cell failing the program verify operation. When sense voltagelevel Vsense is a read voltage, for example, sense amplifier 155detecting a current flow and/or sense amplifier 155 detecting thevoltage level Vdchg may be indicative of the target memory cell having athreshold voltage corresponding to (e.g., assigned to) a differentparticular data value and thus may be indicative of target memory cellstoring that data value.

The single-bit-per-cell (e.g., the two-level) reads in the examplesdescribed above in conjunction the examples of FIGS. 1 and 5 and FIGS. 5and 6, may result in an increase (e.g., of about 30 percent) in the rateat which data may be read compared to single-bit-per-cell reads formemory devices where data lines 110-1 and 110-2 are not selectivelyconnected by transistor 150 or by transistors 650-1 and 650-2, butinstead form a continuous data line.

The single-bit-per-cell (e.g., the two-level) programming in theexamples described above in conjunction the examples of FIGS. 1 and 4and FIGS. 6 and 7, may result in an increase (e.g., of about 60 percent)in the rate at which data may be programmed compared tosingle-bit-per-cell programming for memory devices where data lines110-1 and 110-2 are not selectively connected by transistor 150 or bytransistors 650-1 and 650-2, but instead form a continuous data line.

FIG. 8 is a simplified block diagram of an electronic device, e.g., anintegrated circuit device, such as a memory device 800, in communicationwith a controller 830, such as a memory controller, e.g. a hostcontroller, as part of an electronic system, according to an embodiment.Memory device 800 might be a NAND flash memory device, for example.

Controller 830 might include a processor, for example. Controller 830might be coupled to a host, for example, and may receive command signals(or commands), address signals (or addresses), and data signals (ordata) from the host and may output data to the host.

Memory device 800 includes an array of memory cells 804 that mightinclude the array portions shown in the examples of FIG. 1, 2, 3, or 6.Memory array 804 may be what is often referred to as a two-dimensionalarray, where the memory cells might be in a single physical (e.g.,vertical) plane, or a stacked memory array, e.g., what is often referredto as a three-dimensional memory array, where memory cells might be indifferent physical (e.g., vertical) planes. A row decoder 808 and acolumn decoder 810 might be provided to decode address signals. Addresssignals are received and decoded to access memory array 804.

In some examples, memory device 800, e.g., memory array 804, mightinclude a first string of memory cells selectively connected to a firstdata line, a second string of memory cells selectively connected to asecond data line, and a transistor that selectively connects the firstdata line to the second data line. In other examples, memory device 800,e.g., memory array 804, might include a first string of memory cellsselectively connected to a first data line, a second string of memorycells selectively connected to a second data line, a first transistorconnected in series with the first data line, and a second transistorconnected in series with the second data line and the first transistor.

Memory device 800 might also include input/output (I/O) controlcircuitry 812 to manage input of commands, addresses, and data to thememory device 800 as well as the output of data and status informationfrom the memory device 800. An address register 814 is in communicationwith I/O control circuitry 812, and row decoder 808 and column decoder810, to latch the address signals prior to decoding. A command register824 is in communication with I/O control circuitry 812 and control logic816, to latch incoming commands. Control logic 816 controls access tothe memory array 804 in response to the commands and generates statusinformation for the external controller 830. The control logic 816 is incommunication with row decoder 808 and column decoder 810 to control therow decoder 808 and column decoder 810 in response to the addresses.

Control logic 816 can be included in controller 830. Controller 830 caninclude, other circuitry, firmware, software, or the like, whether aloneor in combination. Controller 830 can be an external controller (e.g.,in a separate die from the memory array 804, whether wholly or in part)or an internal controller (e.g., included in a same die as the memoryarray 804). For example, an internal controller might be a state machineor a memory sequencer.

Controller 830, for example, might be configured to cause the memorydevice 800 to operate in a single-level mode of operation, e.g., wherethe memory cells in memory array 804 might be programmed and/or sensedas single-level memory cells, and/or to cause the memory device 800 tooperate in a multilevel mode of operation, e.g., where the memory cellsin memory array 804 might be programmed and/or sensed as multilevelmemory cells. As such, for example, memory device 800 may be configuredto operate in the single-level mode of operation and/or the multilevelmode of operation.

Controller 830 may be configured to cause memory device 800 to performthe methods disclosed herein. In some examples, controller 830 might beconfigured to cause the memory device 800 to perform a method ofprogramming, including activating a transistor to connect first andsecond data lines in series, applying a first voltage to the first andsecond data lines while the transistor is activated, deactivating thetransistor to maintain the first voltage on the first data line,applying a second voltage to the second data line while the transistoris deactivated, connecting the first data line to a first target memorycell while the first voltage is on the first data line, connecting thesecond data line to a second target memory cell while applying thesecond voltage to the second data line, and applying a program voltageto the first and second target memory cells.

In some examples, controller 830 might be configured to cause the memorydevice 800 perform a method of sensing, including applying a sensevoltage to first and second target memory cells, activating a transistorto connect first and second data lines in series, connecting the firsttarget memory cell to the first data line and to a first source andsensing the series-connected first and second data lines while thesecond memory cell is disconnected from the second data line,disconnecting the first target memory cell from the first data line, andconnecting the second target memory cell to the second data line and toa second source and sensing the series-connected first and second datalines while the first memory cell is disconnected from the first dataline.

In some examples, controller 830 might be configured to cause the memorydevice 800 to perform a method of programming, including activating afirst transistor connected in series with a first data line, applying afirst voltage to the first data line while the first transistor isactivated, deactivating the first transistor to maintain the firstvoltage on the first data line, activating a second transistor connectedin series with the first transistor and in series with a second dataline, applying a second voltage to the second data line while the secondtransistor is activated, connecting the first data line to a firsttarget memory cell while the first voltage is on the first data line,connecting the second data line to a second target memory cell whileapplying the second voltage to the second data line, and applying aprogram voltage to the first and second target memory cells.

In some examples, controller 830 might be configured to cause the memorydevice 800 perform a method of sensing, including applying a sensevoltage to first and second target memory cells, activating first andsecond transistors that are connected in series between first and seconddata lines, connecting the first target memory cell to the first dataline and to a first source and sensing a node between the first andsecond transistors while the second memory cell is disconnected from thesecond data line, disconnecting the first target memory cell from thefirst data line, and connecting the second target memory cell to thesecond data line and to a second source and sensing the node while thefirst memory cell is disconnected from the first data line.

Control logic 816 is also in communication with a cache register 818that might include data latches, such as data latch 160. Cache register818 latches data, either incoming or outgoing, as directed by controllogic 816 to temporarily store data while the memory array 804 is busywriting or reading, respectively, other data. During a write operation,data is passed from the cache register 818 to data register 820, e.g.,that might include a page buffer, such as the page buffers 158-1 and158-2, and a sense amplifier, such as sense amplifier 155, for transferto the memory array 804; then new data is latched in the cache register818 from the I/O control circuitry 812. During a read operation, data ispassed from the cache register 818 to the I/O control circuitry 812 foroutput to controller 830 and subsequent output to a host; then new datais passed from the data register 820 to the cache register 818. A statusregister 822 is in communication with I/O control circuitry 812 andcontrol logic 816 to latch the status information for output to thecontroller 830.

Memory device 800 receives control signals at control logic 816 fromcontroller 830 over a control link 832. The control signals may includeat least a chip enable CE#, a command latch enable CLE, an address latchenable ALE, and a write enable WE#. Memory device 800 receives commandsignals (which represent commands), address signals (which representaddresses), and data signals (which represent data) from controller 830over a multiplexed input/output (I/O) bus 834 and outputs data tocontroller 830 over I/O bus 834.

For example, the commands are received over input/output (I/O) pins[7:0] of I/O bus 834 at I/O control circuitry 812 and are written intocommand register 824. The addresses are received over input/output (I/O)pins [7:0] of bus 834 at I/O control circuitry 812 and are written intoaddress register 814. The data are received over input/output (I/O) pins[7:0] for an 8-bit device or input/output (I/O) pins [15:0] for a 16-bitdevice at I/O control circuitry 812 and are written into cache register818. The data are subsequently written into data register 820 forprogramming memory array 804. For another embodiment, cache register 818may be omitted, and the data are written directly into data register820. Data are also output over input/output (I/O) pins [7:0] for an8-bit device or input/output (I/O) pins [15:0] for a 16-bit device.

It will be appreciated by those skilled in the art that additionalcircuitry and signals can be provided, and that the memory device 800 ofFIG. 8 has been simplified. It should be recognized that thefunctionality of the various block components described with referenceto FIG. 8 may not necessarily be segregated to distinct components orcomponent portions of an integrated circuit device. For example, asingle component or component portion of an integrated circuit devicecould be adapted to perform the functionality of more than one blockcomponent of FIG. 8. Alternatively, one or more components or componentportions of an integrated circuit device could be combined to performthe functionality of a single block component of FIG. 8.

Additionally, while specific I/O pins are described in accordance withpopular conventions for receipt and output of the various signals, it isnoted that other combinations or numbers of I/O pins may be used in thevarious embodiments.

CONCLUSION

Although specific examples have been illustrated and described herein,it will be appreciated by those of ordinary skill in the art that anyarrangement that is calculated to achieve the same purpose may besubstituted for the specific examples shown. Many adaptations of theexamples will be apparent to those of ordinary skill in the art.Accordingly, this application is intended to cover any adaptations orvariations of the examples.

What is claimed is:
 1. A memory device, comprising: a first string ofmemory cells selectively electrically connected to a first data line; asecond string of memory cells selectively electrically connected to asecond data line; a transistor that selectively electrically connectsthe first data line to the second data line; and a plurality of buffersconnected in series with the second data line; wherein respective onesof at least a portion of the plurality of page buffers are respectivelyused for different ones of a first number of bits of data for a memorycell in either the first string or the second string when the memorydevice is operating the first string and the second string in a firstmode of operation, and wherein, when the memory device is operating thefirst string and the second string in a second mode of operation,respective ones of one or more page buffers of the plurality of pagebuffers are respectively used for respective ones of one or more bits ofdata for a memory cell in the first string and respective ones of one ormore other page buffers of the plurality of page buffers arerespectively used for respective ones of one or more bits of data for amemory cell in the second string, wherein the first number of bits isgreater than a number of the one or more bits of the data for the memorycell in the first string and a number of the one or more bits of thedata for the memory cell in the second string.
 2. A memory device,comprising: a first string of memory cells selectively connected to afirst data line; a second string of memory cells selectively connectedto a second data line; a first transistor connected in series with thefirst data line; a second transistor connected in series with the seconddata line and the first transistor; and a plurality of page buffersconnected to a node between the first transistor and the secondtransistor; wherein the first transistor selectively connects theplurality of page buffers in parallel to the first data line and thesecond transistor selectively connects the plurality of page buffers inparallel to the second data line; and wherein respective ones of atleast a portion of the plurality of page buffers are respectively usedfor different ones of a first number of bits of data for a memory cellin either the first string or the second string when the memory deviceis operating the first string and the second string in a first mode ofoperation, and wherein, when the memory device is operating the firststring and the second string in a second mode of operation, respectiveones of one or more page buffers of the plurality of page buffers arerespectively used for respective ones of one or more bits of data for amemory cell in the first string and respective ones of one or more otherpage buffers of the plurality of page buffers are respectively used forrespective ones of one or more bits of data for a memory cell in thesecond string, wherein the first number of bits is greater than a numberof the one or more bits of the data for the memory cell in the firststring and a number of the one or more bits of the data for the memorycell in the second string.
 3. The memory device of claim 2, furthercomprising a sense amplifier connected between the node and theplurality of page buffers.
 4. The memory device of claim 2, furthercomprising a data latch connected to the node and the plurality of pagebuffers.
 5. A memory device, comprising: a first string of memory cellsselectively electrically connected to a first data line; a second stringof memory cells selectively electrically connected to a second dataline; a transistor that selectively electrically connects the first dataline to the second data line; and a sense amplifier, a plurality of pagebuffers, and a data latch connected in series with the second data line;wherein first and second page buffers of the plurality of page buffersare respectively used to receive respective ones of two bits to beprogrammed to a memory cell of the first string of memory cells when thememory cells of the first string of memory cells are operating astwo-bit memory cells, and wherein the first and second page buffers ofthe plurality of page buffers are respectively used to receive one bitto be programmed to the memory cell of the first string of memory cellsand one bit to be programmed to a memory cell of the second string ofmemory cells when the memory cells of the first and second strings ofmemory cells are operating as single-bit memory cells.
 6. A memorydevice, comprising: a first string of memory cells selectivelyelectrically connected to a first data line; a second string of memorycells selectively electrically connected to a second data line; atransistor that selectively electrically connects the first data line tothe second data line; and a sense amplifier, a plurality of pagebuffers, and a data latch connected in series with the second data line;wherein first and second page buffers of the plurality of page buffersare respectively used to receive respective ones of two bits read from amemory cell of the first string of memory cells when the memory cells ofthe first string of memory cells are operating as two-bit memory cells,and wherein the first and second page buffers of the plurality of pagebuffers are respectively used to receive one bit read from the memorycell of the first string of memory cells and one bit read from a memorycell of the second string of memory cells when the memory cells in thefirst and second strings of memory cells are operating as single-bitmemory cells.